Flux Lab Acoustics

Flux Lab Acoustics is a Ukrainian company dedicated to the design and manufacturing of high-end audio products. The company is well regarded in the audiophile community and their portfolio includes many successful and well awarded products, like the Flux FCN-10 or the FA-12 headphone amplifiers. Their products are famous for combining excellent sonic performance and build quality at very reasonable prices.

The Russian invasion of Ukraine ruined their business and Flux Lab Acoustics was forced to cease production. Thankfully none of the team or their families was fatally wounded and now that the Russians have retreated back, Flux were able to resume production at their own facilities in Kharkiv.

Their new creation is the Mentor, a headphone amplifier born during war, under very difficult conditions and this means a lot about the dedication and the internal strength of the Flux Lab team.



Flux Mentor

The Flux Mentor is a Class-A, dual mono headphone amplifier with many technical innovations

The output stage operates in class A, which allows transmitting signals of small amplitude with the highest accuracy. The amplifier circuitry uses J-Fet transistors at the input for a meaty and smooth sound, and bipolar transistors at the output, specially designed for use in high-end audio circuits, to deliver the highest fidelity and transparency. The power supply for the amplifier circuitry is 70 volts to ensure uncompromising dynamic performance with the most demanding headphones on the market.

Class-A produces a lot of heat that needs to be effectively dissipated and in order to do so, Flux have refined the heat sink design. The amplifier circuitry is promptly prepared for utilization, and subsequently shares its greatest sound quality only after a mere 15 minutes. In addition they have partially placed the heat sink under some of the PCB components, which allows the amplifier circuitry to start up faster and provides better thermal stability for the entire circuitry.

The amplifier is built on the dual mono principle, with each channel having its own power supply and power transformer. The power supply for each channel uses four high-capacity capacitors manufactured by Cornell Dubilier Electronics, capable of delivering significant current at their output and having a low output impedance.

The power supply utilizes custom power transformers with a very low dissipation field and noise. This permits the amplifier circuit to function without any apparent hum, even when using high-sensitivity headphones. Flux have also used an Ultra Pure Oxygen Free Copper (UP-OFC) power cable with additional shielding from Neotech from the AC inlet socket to the power transformers.

The volume control is based on a relay attenuator and contains 64 steps. The control circuit uses Panasonic fast signal relays with low contact resistance. The analog signal is fed to the relay attenuator located next to the input sockets, and the ALPS variable potentiometer (Blue Velvet series) is used for control only.

The Flux Mentor supports a feature that allows the synchronization of two amplifier units in a dual mono mode for an even greater power reserve. Each channel of the amplifier operates in a fully balanced mode. You simply select which unit is the master and which is the slave. The synchronization system also allows you to control the operation of the second amplifier, so that when the master unit is switched on, the second unit is automatically switched on.

A dual mono Mentor stuck in mono mode is able to produce 33.5W RMS per channel at 32Ω and 6.4W RMS per channel at 300Ω, a huge amount of power that can ransack every headphone in existence or even run your speakers. You can order the Mentor with or without the mono module.

FLUX guarantees an absolutely identical volume level between the two units, even if the second unit is purchased much later. The differences may be primarily due to the tone of the front panels, as there are slight differences from batch to batch.

Components and PCB

The high quality components used in the circuits include Takman resistors (Rex and Rey series), extremely expensive Vishay VAR series uncased audio resistors, PRP resistors, Cornell Dubilier, Nichicon, Wima, and Epcos capacitors.

The internal PCB features exquisite craftsmanship, most components are through hole, the quality of the soldering, the cabling and the assembly are really marvelous.



Remote control

The Mentor supports remote control for volume adjustment and mute/unmute functions.
The high quality, all aluminum, remote control is optional and available for $50 extra. It could have been included as a standard but on the other hand it saves some money for people who don't need one.

The remote control adjusts the volume without moving the volume knob. Every time you touch the knob, the volume automatically reverts to its given position.



Power cable upgrade

The designer suggests that you will get the most out of the Mentor only if you use a high quality power cable. You can use your favorite brand or consider Flux Lab custom-made power cable. It is based on an NEP-5002 conductor from Neotech that features thick conductors (0.42mm) of ultra-pure oxygen-free copper (UP-OFC). The ground conductor’s smaller cross-section (1.43mm) results in a slim and flexible cable for a better user experience. The cable provides complete protection from external electromagnetic radiation, thanks to an internal aluminum foil shield and a drain wire. Filling the free volume with synthetic fiber ensures comfortable flexibility and a “memory” effect, allowing the cable to be easily positioned and maintained in the desired position. Each cable is hand-crafted in the Flux Lab workshop and equipped with high-quality TTAF 93047/048 connectors with gold-plated brass and copper contact groups. The cable is supplied in a length of 1.8 meters (6 feet) and is available as a $100 extra purchase when you place your order for the Mentor.



Non Audio stuff

The chassis of the Mentor is made from black painted metal sheet. The front panel and the impressively massive volume knob, which is custom made, are from one piece, solid aluminum alloy. They are painted with a high quality and very smooth finish that is available in two color options, titanium gray and coal black.

The sturdy and well made chassis comes with four anti-vibration feet installed as a standard.

The only thing of note is the rather odd shape of the chassis which measures 342x397x82mm thus making it more deep and less wide than the industry standard so you might have a problem placing it above or underneath other audio components.

The Flux Mentor is a headphone amplifier without a preamplifier output function or any digital inputs. It has balanced XLR and single ended RCA line inputs that are located at the back of the unit. You can have both of them simultaneously plugged in and select the desired one from the corresponding switch at the front. The back also houses the AC input and the optional synchronization interface.

The minimalist front face has power on/off, input and gain switches located at the left, the dominating volume knob at the middle and two headphone outputs at the right. The first is a combined 6.35mm jack and 3-pin XLR for the mono mode while the second is a 4-pin XLR.



Let's talk about power

The power output of a single Mentor is 11.2W (32Ω) and 1.6W (300Ω) RMS per channel so it easily ranks amongst the most powerful amplifiers in the market. In order to cater for different headphone loads, Flux have included three gain settings (low-14dB, medium-20dB and high-25.3dB) that can be selected from a switch at the front panel.

The stepped attenuator is well programmed and makes fine adjustments with every “click”, not too loud, not too quiet. To get a rough idea about the power output and the volume adjustment range of the Mentor, the Focal Clear Mg needs about 21 steps to get from silence to pretty loud at low gain setting and the HIFIMAN Susvara 30 steps at high gain. Volume alone doesn't mean much though, what matters the most is that the Mentor drives the Susvara with great dynamic range, excellent control, strong grip and surplus of headroom.

The Mentor is a powerhouse but the low gain is so well designed that it can also drive sensitive earphones without getting loud too early. As an example, the FiiO FX15 needs 18 steps to get comfortably loud.

The Flux Mentor doesn't get hot as other Class-A amplifiers, it only becomes mildly warm under the bottom of the chassis. The rest of the chassis stays cool even under stress conditions.

As per usual practice the Flux Mentor was left playing music for about 150 hours before listening evaluation.

The Flux Mentor was tested with the Neotech power upgrade cable.

All headphone cables that were used during the evaluation are made by Lavricables.



Audio stuff

The Mentor is dead silent without the faintest background hiss even when used with very sensitive earphones. A pitch black background that helps all the finest sonic particles to emerge and surface from the depths of the recording in a pure and naturally flowing way so the sound is full of detail but never becomes analytical or sterile. The sound of silence is audible and extremely beneficial for the sonic performance of the Mentor which has an eerie and spooky calmness, a quietness that only the best “high end” amplifiers have.

You don't have to listen a lot in order to realize that the Flux Mentor has class leading transparency and impressive scaling potential. It is a high-end amplifier with a mirror-like fidelity that must be paired with the best possible sources in order to unveil its full glory. The Mentor will never become the bottleneck of your system, no matter how good your source and your headphones are, it will always deliver its best and make sure to highlight every last bit of their unique sonic characteristics. On the contrary, there is a strong possibility that source and headphones might become the limiting factors if they are not up to the task.

I have started my listening sessions with trusted mid-range sources, like the Aune X8 XVIII and the Volumio Primo, soon to discover that despite having good results from the beginning, I always felt that the Mentor could do much better.

My next move was to switch to the HIFIMAN Serenade, the Denafrips Pontus II and the Lab 12 dac1 reference (custom edition) that all of them perform admirably well, greatly surpassing their asking price. At last, now everything felt at place and the combination unveiled all the sonic virtues of the Flux Mentor or the Mentor unveiled all the sonic virtues of the sources, read it the way you like! Still I am pretty sure that if I owned better sources, the Mentor could have sounded even better.

The Mentor is not some kind of a snobbish amplifier though, you can always enjoy it with your favorite sources in a never ending musical journey that might eventually lead you to an upgrade path.

With the Mentor there is no such thing as headphone matching, the amplifier pairs exemplary well with virtually all kinds of headphones as it mirrors their own sound signature with the most impressive fidelity. I have enjoyed pretty much everything, from the Sennheiser HD660S2 to the HIFIMAN Arya Organic, the Meze Elite and the HIFIMAN Susvara. The better the headphone I used, the better was the performance of the Mentor.

At this point someone could rightfully ask - is the Flux Mentor like a “wire with gain” kind of an amplifier? The only things you have been talking about are fidelity and transparency.

Well, not exactly, the Mentor is exactly the opposite, this is an amplifier painstakingly tuned by ear to combine transparency and fidelity with deep musicality and astonishing levels of engagement. It took months of fine tuning to give Mentor its sound signature which is flowing, effortless, natural, immersive and communicative without calling attention to itself.

The amplifier is synonymous with precision and calmness, it is not producing short lived glowing pyrotechnics that may sound impressive and imposing at the beginning but fail to communicate the true essence of the music at the end.

The Mentor is a silent force, a mature and sophisticated sounding amplifier that very carefully balances technicalities and musicality in the exact needed amounts to make your music sound as realistic as possible while at the same time respecting the sonic characteristics of the source and the headphones used.

The amplifier is dynamic and impactful but not in a brutal way, it is fast, precise and accurate with crystalline clarity and strong presence in the whole frequency range but everything is done in a way that oozes aristocratic politeness. The Mentor is not raw or bold sounding, this is an intellectual amplifier that will play with your mind and heart rather than excite your primitive instincts.

Music break

One of the albums that I have listened with the Mentor was Handel's opera Alcina. The listening experience with the Mentor and the Lab 12 dac1 reference was simply magnificent. I have used both the Susvara and the Elite.



More audio stuff

The overall resolution and refinement of the Mentor are astounding, especially in the treble which sounds silky smooth and ethereal but never lacking in extension and energy. The mid-range is larger than life, spacious, and articulated with natural voicing while the bass has impressive layering and definition. The timbre is extra natural and realistic with the most organic characteristics. Acoustic music sounds convincingly lifelike while the Mentor has all the technical prowess to handle all kinds of music.

The sound is smooth and mildly warm but not mellow or dark, the flowing music is full of colorful harmonies and overtones, like a meadow full of spring flowers and thousands of butterflies. The texture is weighty and and visceral, every single note is heard weighty and full of substance. The amplifier has excellent timing, the music fades away in the most natural manner, not fast not too slow, the time that passes for the moment a note is born till it dies is exactly as it was captured in the recording.

The soundstage of the Mentor is both deep and expanded but in a natural way without artificiality added width or depth. Separation is phenomenal, both in the vertical and horizontal plane, the Mentor has class leading positioning accuracy and imaging. The presentation is grand and holographic, the listening experience is immersive, large symphonic works sound really impressive, the listener feels like sitting a couple of rows behind the conductor, enjoying the full glory of the symphony orchestra which is re-created with a finely sculptured relief. The Mentor also excels in reproducing all the ambient information that was captured in a high quality recording thus making the listening experience even more realistic.

The competition

Other solid state amplifiers that I have reviewed and are worth mentioning as possible alternatives to the Flux Mentor are the Violectric V222, V340 and V550. The sonic characteristics of the Mentor are rather closer to the flagship V550 than the other two models. The V222 is warmer with a more tube-like character but it can't match the precision, the resolution and the transparency of the Mentor while the V340 gets close enough but not as much as the V550.

The truth is that the Violectric V550 and the Flux Mentor share a lot of common characteristics regarding their transparency, precision and mirror-like fidelity. Additionally both sound musical and engaging and none of them is clinical or sterile despite their flagship technicalities.

A difference is that the Flux Mentor is a calmer and more polite amplifier, the sound approach is more sophisticated and civilized when compared with the muscular brutality and the raw power of the Violectric V550. The V550 is more impactful on the low-end and energetic in the treble while it has an edge when it comes to overall clarity and transparency. What doesn't have though is that delightful Class-A timbre of the Mentor which makes it sound more organic and natural than the V550, the music has better fluidity and a greater sense of realism in the Flux Mentor that is additionally more holographic and immersive sounding than its German colleague.

The Violectric V550 is also a high-end balanced preamplifier and is built around an all aluminum chassis but it is considerably more expensive than the Flux Mentor and you have to spend even more money to upgrade to the V550 PRO in order to get a stepped attenuator that is included as a standard in the Flux Mentor.

Conclusion

Some of the best human creations were made during war time. The Flux Mentor is a masterpiece, a mature and very sophisticated amplifier that has all the right ingredients in the exact needed amounts to make the perfect sonic dish. Honestly, high-end was never so affordable before the making of the Flux Mentor. The Flux Lab Acoustics have made an end-game solid state amplifier that you can buy and stop worrying about future upgrades. The Flux Mentor is easily the most affordable, high-end headphone amplifier on the planet with an insane value for money ratio and one of the best - if not the best - bargains in the audio industry.

The review sample was kindly provided free of charge in exchange for an honest review.

The Flux Mentor is available from here. The base price for a single Flux Mentor is $1229 and $1299 with the additional mono input so a dual mono set-up costs $2599. All orders are dispatched from a warehouse in Poland so EU customers will not have to deal with import fees and tax.

A deluxe version of the review is available in my website.

This is the world premiere review of the FLUX Mentor headphone amplifier.

The iFi iDSD Diablo 2 is the successor of the original iFi iDSD Diablo which was one of the most powerful, battery powered portable DAC/amps in the market. This updated version of the product adds several new features as we are going to find out later on.

Technical highlights

The Diablo 2 is a battery powered DAC/amp that can be used at home and mobile. The DAC chip used is a Burr-Brown True Native chipset that offers ‘bit-perfect’ decoding. An XMOS 16-Core chip processes the audio data received via the USB and S/PDIF digital inputs while a GMT (Global Master Timing) femto-precision clock and intelligent memory buffer are used for jitter eradication. The Diablo 2 supports PCM 768kHz, DSD512 and full MQA decoding.

Unlike other iFi DACs, like the NEO iDSD 2, the Diablo 2 doesn't include the analogue processing modes, XSpace and XBass II, and it doesn't support digital filters other than the bit perfect.

A fully balanced dual-mono circuitry, called PureWave, elevates clarity by separating channels and reducing noise while DirectDrive removes the need for coupling capacitors and OptimaLoop employs tailored multiple feedback paths in the amplifiers, refining gain control and reducing distortion.

The Diablo 2 supports xMEMS solid-state micro-speaker technology, enhancing performance of compatible IEMs and headphones.

Contrary to the original Diablo, the iFi Diablo 2 features wireless Bluetooth 5.4 reception with support of the new aptX Lossless codec for lossless CD-quality streaming. This codec is not yet that widespread but you shouldn't be worried as the Diablo 2 is also compatible with the aptX Adaptive, aptX, LDAC, LHDC/HWA, AAC and SBC codecs. Bluetooth reception is strong and stable while sound quality is exceptionally good with some degradation, most notably in the treble.

Extra features vs the iFi Diablo 1

When compared to the original iFi Diablo, the Diablo 2 has improved power supply and amplifier designs that translate in a 52% increase in balanced power output at 32Ω and 405% increase in balanced power output compared to the SE output at 600Ω. Additionally the new model features a Quietline control system, iEMatch for 3.5mm and 4.4mm, Bluetooth (Lossless) input, support for xMEMS, MQA over SPDIF, USB Type-C input, a volume locking mechanism and enhanced analogue volume control with improved accuracy (+/-0.6dB vs. 1.5dB before). The downsides are that the iFi Diablo 2 is bigger, heavier and $300 more expensive than the original.

Non Audio stuff

The iFi Diablo 2 has grown bigger and heavier (166x85x28.5mm/455g) than the already big Diablo so it is not exactly portable but rather transportable. This is not a device that can fit in your pocket, you are going to need a small carrying bag for moving around with it. Thankfully a high quality carrying case is included in the package.

The minimalistic and industrial design resembles that of its predecessor but now it has twenty-two curved rails for improved cooling performance. Eight of these rails are compatible with four wind shaped stands that are included in the package and can be used to position the device vertically or horizontally to save space. The red/gray aluminum chassis is very well made and looks extremely sturdy, the only thing of note is that the back side has corners and edges that are a little sharp. Those engraved channels might work well, because the Diablo 2 runs very cool, but they attract dirt and are difficult to clean.

The generously accessorized package includes long USB type-C to C, short USB type-C and lighting cables together with a USB type-A adapter. Another cable converts the barrel jack of the included iPower 2 power supply to a USB type-C jack. There are also included 3.5mm to optical and 6.35mm jack adapters and an iFi travel case with a shoulder strap.

At the front face of the Diablo 2 you can see two headphone outputs (6.35mm and 4.4mm), xMEMS and gain switches, a volume control knob, with a newly added lock mechanism that prevents accidental adjustments, and a LED that displays the input sampling rate.

At the back panel there are two USB type-C ports, one for data input and one for charging, a S/PDIF 3.5mm input, a 4.4mm line input/output, a battery status LED and the input selection button. Positioning the battery status LED at the back was not a smart idea as it is not practical at all.

Pressing the input button once will place the Diablo 2 into Bluetooth pairing mode. The other digital inputs are automatically detected, the USB has priority over S/PDIF and both over line input. The line input is 3.5mm only and in order to work you must have all digital inputs unplugged and Bluetooth switched off. Otherwise this jack will work as a line output.

Battery and DC mode

The power source of the iFi Diablo 2 is a 4800mAh battery that gets charged by a dedicated USB type-C port so it is possible to charge and do USB decoding at the same time. The battery needs about 5 hours for a full charge and its duration ranges from 8-9 hours at the best, to 5 hours depending on the load, the gain setting and whether the Bluetooth is enabled or not. The unit sports an auto power off feature that shuts it down after about half an hour or inactivity.

An additional feature of the iFi Diablo 2 is that it can be powered by mains. The bundled 5V iPower 2 power supply features Active Noise Cancellation II, effectively canceling out all incoming EMI and RFI noise. Unlike the FiiO Q7 there is no switch to manually enable the DC desktop mode and bypass the internal battery. The procedure is automatic, and there is no way of physically switching it. The way it works is that once plugged in and the battery gets fully charged, it switches internally to the mains power and only supplies battery power when it falls below a certain level.



Audio stuff

The Diablo 1 was already a very powerful portable DAC/amp but its low gain setting was too aggressive for use with sensitive earphones. The iFi Diablo 2 is even more powerful than its predecessor and additionally it fixes this issue by incorporating a third gain setting and iFi’s iEMatch technology. This feature is tailored for high-sensitivity headphones and earphones as it removes background noise and increases the usable volume range. The feature is enabled by a switch located underneath and is separately available for the 6.35mm and 4.4mm headphone jacks.

The Diablo 2 offers three power modes: Normal for IEMs, Turbo for mid-sensitivity headphones, and Nitro for demanding headphones, boasting a 19.2V maximum output. The maximum RMS power output of the 4.4mm jack is 19.2V/611mW (600Ω), 7.4V/1710mW (32Ω) and 11.5V/2060mW (64Ω). Furthermore the Diablo 2 has a unique design that allows it to offer a max peak power of ~5.2W(32Ω) per channel thus allowing exceptional headroom.

To get a rough idea about the actual performance of the Diablo 2, the Focal Clear Mg gets pretty loud halfway the volume range (normal gain/4.4mn) and the same applies to the sensitive FiiO FX15 but this time with the iEMatch enabled. The Diablo 2 has absolutely no problem driving headphones like the Sennheiser HD660S2 while it is one of the few portable, battery powered amps that can sufficiently drive the HIFIMAN Susvara. The amplifier is also dead silent and noise free when used with very sensitive IEMs like the Soundz Avant.

The overall sound signature of the iFi Diablo 2 sits somewhere between the original Diablo and the iFi NEO iDSD 2. The Diablo 1 was surprisingly neutral and flat sounding for an iFi product (just like the NEO iDSD) while the NEO iDSD 2 has a warmer and more organic sound presentation, quite reminiscent of an analog set-up. The Diablo 2 is a bit warmer and more euphonic sounding than the Diablo 1 but not as much as the NEO iDSD 2. What we have here is a well thought balance between class-leading transparency and neutrality with an engaging and musical character that will make your music sound alive and lifelike with respect to the recording.

The Diablo 2 has a powerful and dynamic low-end, the bass is punchy, impactful and realistically contrasted. The texture is not as visceral as in the NEO iDSD 2 but is weightier and not as lean and dry as it was in the Diablo 1.

Slightly warm, speedy, tight and controlled with excellent definition and top-tier layering, the Diablo 2 will shake all your headphones and unleash deep bass while offering technicalities of the highest level.

The iFi Diablo 2 is still a little bit aggressive and vibrant but not as nervous and exposing as its predecessor. This time it is much easier to match with various headphones, even brighter ones, as the treble is relatively smoother and not as bright or sharp while the mid-range is linear and neutrally tuned without accentuation.

The sound is sparkling and energetic but the timbre manages to stay rather natural and realistic, the Diablo 2 has a hint of warmth and plenty of harmonic variety that were slightly missing from the original model. Voices and instruments sound lifelike as they have excellent tonal and timbral accuracy. The textures are full and weighty, the sound is devoid of any severe artificiality and is not sterile. Detail retrieval is excellent but Diablo 2 avoids the trap of sounding analytical and clinical.

The Diablo 2 poses sound fluidity and sonic richness while it offers top shelf resolution and refinement as someone would expect from a flagship product. The soundstage is both deep and expansive, given that you have an equally skilled headphone. There is plenty of ambient information on tap, the Diablo 2 is exceptionally skillful when it comes to imaging accuracy and will make your headphones sound grand and immersive.

Comparison with FiiO Q7

The $799 Q7 is FiiO's flagship portable (transportable) DAC/amp boasting similar features with the iFi Diablo 2. It uses a single ES9038PRO DAC chip in a fully balanced configuration with dual THX AAA 788+ amplifiers that can do 3WPC (32Ω) in desktop mode and 1.5WPC (32Ω) in battery mode.



The FiiO Q7 features a manually switched DC desktop mode that completely bypasses the internal battery. The downside is that you need a 12V power supply to do the job when the Diablo 2 can be DC powered by a 5V phone charger. The Q7 supports Bluetooth connectivity but without the aptX lossless codec, it has a couple of more digital inputs and analog outputs but it doesn't support line input. The Q7 also has a tiny OLED screen and is compatible with the FiiO control application that allows deeper customization. The Q7 measures 158.4x88.5x28.3mm and weighs 620g compared to the 166x85x28.5mm and 455g of the Diablo 2.

When it comes to sound, the most notable difference is that the FiiO Q7 is a bit more technical and transparent sounding than the Diablo 2 but also a little sharper and less organic. The Q7 is more dynamic and impactful than the Diablo 2 but it has drier and somewhat leaner textures while it is a tad less forgiving and more exposing. Resolution is on the same level for both and while the Q7 has marginally sharper imaging than the Diablo 2, the soundstage is not as holographic and immersive as in the Diablo 2.

Conclusion

Species keep evolving, constantly adapting to their surroundings to become better and stronger than their ancestors. The same happened with the Diablo that successfully evolved to the Diablo 2 which is more powerful with better sound quality and many new features than its predecessor. Not without a cost of course as it is also bigger and more expensive than the Diablo 1. The iFi Diablo 2 belongs to a new generation of products that are designed to be used as portable and desktop, all-in-one, audio devices at the same time. It is a flagship level product with features and audio performance that can justify the price of admission but the truth is that it would be more competitive and better value for money if price was a little lower.

The iFi Diablo 2 was provided as a loan and now is returned back.

The price of the Diablo 2 is $1299 and you can buy one from iFi shop.

A more comprehensive version of the review is available in my website.

Introduction

The Burson Playmate 2 is a compact sized, all-in-one DAC and headphone amplifier, representing a significant evolution from its predecessor, merging aesthetics with high-end functionality.

The Playmate 2 is equipped with a single ES9038Q2M DAC chip and Xmos USB input, supporting high-resolution audio formats up to 32bit/768kHz PCM and DSD512. The unit is compatible with Android, Windows and Mac operating systems.

The discrete headphone amplifier of the Playmate 2 is operating in pure class-A and offers 3W/16Ω with two gain levels for perfect headphone matching.

A novelty feature of the Playmate 2 (and all other Burson Audio devices) is that it allows for sound tuning through op-amp rolling thanks to the four detachable DIP sockets. The only thing that the user has to do is to unscrew and take the lid off in order to access the DIP sockets. The Playmate 2 comes with 2 x NE5532 and 2 x NE5534 op-amps pre-installed that can be rolled with compatible op-amps, like the Burson Audio, Vivid discrete op-amps.

Another feature that Burson Audio has implemented in the Playmate 2 is their proprietary Max Current Power Supply that greatly enhances audio quality.

Non Audio stuff

The Burson Playmate 2 is a compact sized device with a chassis that is made from precision-machined aluminum alloy with a special design in order to function as a unified heat-sink. This is a solid and well made device with an industrial look and a compact size that can fit virtually anywhere. There is also the option to buy a stand for vertical positioning to save even more space. The only thing of consideration is that the deeply engraved lines of the chassis are dust magnets and need regular cleaning.

The Playmate 2 is a headphone DAC/amp that also has a variable RCA line output that can be used as a preamplifier for active monitors or a power amplifier. The device doesn't have a line input and the digital inputs are limited to USB type-C and optical, missing a coaxial one. All these are located at the back together with a 24V/3A DC input where you connect the external power adapter.

The front face has a tiny OLED screen located at the center, a multifunction knob, a 6.35mm headphone jack and a 3.5mm jack that also doubles as an HD microphone input for gaming. The package includes a mic splitter so you can have a microphone and a headphone simultaneously plugged.

The screen displays information like volume level and input sampling rate while it is used to navigate through the configuration menu where you can set various parameters, like amplifier gain and digital filters. You must have eagle vision though because the digits are so small that are almost impossible to read. Another thing of consideration is that the multifunction knob doesn't respond to every step, sometimes you need two or three continuous clicks to register an action and this also applies to volume setting. I do think that the remote control should have been included as a standard accessory.

The package includes a USB type-C cable, a mic splitter, the external power adapter and a hex key for removing the lid in order to access the op-amps.



Audio stuff

The power output of the Playmate 2 is 3.5W/16Ω or 2.5W/32Ω with a 2Ω of output impedance and plenty of instantaneous current supply thanks to the innovative power supply. The Playmate 2 can drive both low and high Z headphones no matter their sensitivity minus some really difficult loads like the HIFIMAN Susvara. The Playmate 2 didn't break a sweat with headphones as diverse as the Focal Clear Mg, the HIFIMAN Arya Organic, the iBasso SR3 or the Sennheiser HD660S2 but it gets loud too fast with sensitive loads even at low gain.

The Playmate 2 is silent enough for use with regular headphones but it produces some noise and hiss with sensitive earphones. You can use the Burson Audio Super Charger, low noise power supply, which considerably lowers noise floor but still the Playmate 2 is not an ideal match with sensitive earphones. Another thing of criticism is that the amplifier makes a loud “pop” noise when switching on and off, there is no “pop” elimination circuit.



The ES9038Q2M is a widely used DAC chip that can sound from ultra linear and too technical to quite natural and organic depending on the implementation and whether the designer chooses to highlight its technicalities or add some extra musicality. Usually everything has to do with the design of the output stage and the headphone amplifier, and the Playmate 2 has some aces under its sleeve.

Burson Audio has opted for a tuning that is vastly different from the current trend of THX or current feedback amplifiers that aim for the best possible technicalities and measurements but usually end sounding sterile, clinical and lifeless without any significant ambient reverb.

The Burson Playmate 2 has a smooth, musical and rather laid back sound signature where timbre realism and texture shaping are prioritized over strict technicalities. Don't take this wrong though, the Playmate 2 is quite competitive when it comes to transparency, definition and clarity, it can offer good detail retrieval and satisfying layering but in a relaxed manner without letting technicalities become dominant and suppressive.

The Playmate's 2 sound is about harmony and melody, the presentation is rich and harmonious, weighty and full bodied with colorful overtones and realistic timbre. The treble has minimum artificiality and digital glare, it is smooth and rather forgiving without any roughness or harshness. Still, it is not dark or muted and it doesn't lack in extension, energy and clarity. The mid-range is present and transparent with nice articulation and satisfying resolution. Voices and instruments are reproduced full bodied and lush, they sound lifelike, euphonic and organic. The bass is weighty yet tight and controlled. Layering, definition and dynamics are good but not class leading, competition can fare better in these departments but what you get in exchange is a warmer and considerably more visceral low-end which can be used to fill lean and dry sounding headphones.

The soundstage of the Playmate 2 is wide and spacious with good depth layering and height. Positioning accuracy and imaging are good but they can be bettered by some more technical sounding amplifiers, however they will have a really hard time to match the holography and the grandness of the Playmate 2. Additionally, most THX implementations are not that great in reproducing the ambience atmosphere of a recording, they sound flat and lifeless when the Playmate 2 really excels by adding extra fluidity to the music.

Against the competition

The main section of review describes how different is the sound signature of the Playmate 2 when compared to amplifiers that employ op-amp designs in their output states. So the question is how it fares against similarly priced DAC/amps that also have discrete output stages, like the $520 Yulong Aurora or the $320 Aune X1s GT.

Well, the answer is that the sonic performance of the Playmate 2 is very competitive and such audio devices share a similar kind of sound shaping, each one with its own advantages and disadvantages. The main differences have more to do with functionality and interface rather than sound. So in the case of the above mentioned devices you can get balanced headphone or line outputs, more digital inputs, Bluetooth connectivity or even a line input in the case of the Aurora, but none of them offers the ability to exchange op-amps and roll the sound of your preference. Additionally the Playmate 2 is focused on single-ended performance when the other two are fully enjoyed from their balanced outputs so the Playmate 2 is more recommended if you have single-ended headphones.

Conclusion

Thankfully not all audio devices sound the same and not all audio engineers follow the same path when designing. If you are tired of the measurements war and the lack of inspiration that many current audio devices have, then you should put the Playmate 2 in your short list. Musical and engaging with a lush and organic sound signature, this is a DAC/amp that will make your music sound like real music again. It is not without quirks but they can be overlooked in favor of the good sound and the unique ability to easily roll op-amps.

The review sample was kindly provided free of charge.

The price of the Burson Playmate 2 is $544 for the basic version and $744 for the deluxe. The basic version comes with 2 x NE5532 and 2 x NE5534 op-amps installed while the deluxe includes an extra 2 x V6 Vivid dual, 2 x V6 Vivid single op-amps and a remote control. Both can be ordered from the Burson Audio online shop.

A More comprehensive version of the review is available in my website.

The Nova is the latest addition in Truthear’s catalog. A hybrid in-ear monitor consisting of 1DD and 4BA per side with a three way crossover. NOVA uses a 10mm diameter specialized dynamic driver to take charge of the bass and a composite full-frequency dual balanced armature driver which is responsible for mids and part of trebles. It is combined with a custom composite double balanced armature driver that is responsible for the trebles, further improving the bandwidth while matching the sensitivity of the mid-high frequency composite driver.
Nova adopts a polyurethane suspension composite liquid crystal dome diaphragm and dual-cavity internal magnetic circuit dynamic driver of N52 magnet.

The acoustic waveguide structure with filtering function realized by the high-precision DLP-3D printed technology and the RC frequency division makes the five drivers perform well under different corresponding acoustic waveguides.

Tuning concept

The tuning of the NOVA is realized with slightly less bass gain than the HARMAN IE 2019 curve and is close to the high-frequency amplitude response of HARMAN OE 2013 with high HRTF characteristics. The result is a warm, soft, clear and natural sound thanks to the brand-new overall system design of lowering the Q value.

Non Audio stuff

The 3D printed ear-shells are made by HeyGears using their own medical-grade high-transparency resin which is skin friendly. The ear-shells have an anatomical, custom-like design and despite being a little bulky they are lightweight and comfortable just slightly protruding outside the ear if it is of a smaller size.

The Nova is beautiful looking without attracting too much attention, it combines a black colored main body with an attractive blue faceplate that has a wavy pattern as the main design element.

The Nova comes with a 2-pin detachable cable that is made from single crystal copper wires in 4 strands with 112 cores each. The cable has a rather outdated textile sheathing and pre-shaped ear-hooks. It is soft and lightweight but is little noisy, it gets easily tangled and the 3.5mm plug is not interchangeable.

The Truthear Nova comes in a box beautifully decorated with a printed design of the brand's female mascot. The package includes a set of classic silicone ear-tips in three sizes plus short double-flange and long double-flange ear-tips, as well as foam ear-tips with multiple limiters. The bad resonance peak of the high frequencies will move backwards further with the use of the double-flange ear-tips while foam ear-tips with multiple limiters can meet the different needs for depth insertion. Also included are the detachable cable and a carrying case made from soft, synthetic leather.



Audio Stuff

The Truthear Nova (14.8Ω/123dB) is very easy to drive and for the review I have used the Truthear Shio, the iBasso DC03PRO and the Mojo2.

Harman-target fans have plenty of reasons to rejoice with the Truthear Nova as it is tuned closely following the Harman in-ear target curve. This is an affordable earphone specifically tuned for people who like this target curve.

The Nova has a mid-bass focused tuning that works well with a lot of kinds of music but not that well with classical where certain low pitched instruments will sound out of tune, a little unrealistic and too colored. Sub-bass is also well emphasized and extended making the Nova very fun and enjoyable for casual but not that suitable for audiophile critical listening. The bass is big and imposing, dynamic and impactful, this is the kind of low-end that will definitely please gamers and movie watchers. Additionally the bass on the Nova is quite fast and tight but not that well controlled, it isn't muddy or overly dark and despite its dominance it doesn't cloud the mid-range while the dynamic driver can handle high listening volumes without distortion.

The Nova has an upper mid-range emphasis that is followed by a smooth and slightly subdued treble thus making this particular region the star of the show or a living nightmare, depending on how sensitive your hearing is to this area. Lower mids are slightly underwhelming and play a rather supportive role to the dominant upper mid-range, a tuning concept that adds sparkle, clarity and favors female vocals. Resolution is quite good, the mid-range is crystal clear and well defined with a mostly realistic timbre but you can't fail to notice some tuning imbalances, not all instruments sound equally focused.

The treble is smooth and forgiving without lacking in extension and clarity, it is well defined and energetic but not bright or fatiguing. The Nova is resolving and detailed enough but it has some issues with the texture of its treble, the timbre is not devoid of some BA artificiality and roughness. The fundamentals and overtones of higher pitched instruments can sound a little fake, metallic and too thin to be considered as natural and realistic. This is something particularly audible when listening to instruments like the harpsichord or the violin where their upper register fails to sound convincing enough.

The presentation on the Nova is intimate, the soundstage is moderately wide and the listener feels like sitting next to the stage. The Nova will not earn any praises for its depth layering or holography but positioning accuracy is good so you can easily pick all individual instruments in heavily populated passages.

Conclusion

There are so many earphones at this price range that adhere to the Harman in-ear target curve that something has to be really special in order to stand out from the crowd and take the lead. The Truthear Nova ticks a lot of boxes right but they are not enough to make it better than the competition. On the other hand, except for the tuning concept and the rather competitive technicalities, it might also appeal to you because it is comfortable, lightweight, exceptionally well made, beautiful looking and comes with plenty of accessories at an affordable price.

FiiO is a brand with great expertise in the field of in-ear monitors. Their extensive collection includes many models with various driver configurations and price tags. From the entry level 1DD FiiO JD3 to their previous flagship, the 1DD+6BA FiiO FH9. Yes, you have read that correctly, their previous flagship because the new one is the FiiO FX15. The first tribrid earphone by FiiO to include electrostatic drivers.

Technical

The FiiO FX15 is an 1DD, 1BA and 4 electrostatic drivers, tribrid earphone, the first such made by FiiO.

For the low frequencies, the FX15 features a 10mm DLC dynamic driver, chosen for its high rigidity, high damping coefficient. In order to achieve harmony between the dynamic, BA, and electrostatic drivers, the R&D team specially redesigned the structure of the dynamic driver. A vent at each earpiece helps to relieve the internal pressure and make for a fatigue-free listening experience.

The FX15 adopts the proven Knowles ED-29689 balanced armature driver to handle the mids and lower treble frequency ranges. The R&D team reduced the sensitivity of this BA driver through the shell design and other methods to ensure that the BA and electrostatic drivers output their respective frequency ranges without interference from each other.

The star of the show are the four electrostatic drivers by Sonion that mostly handle the high and ultra-high frequencies above 15kHz. FiiO has added a switch that specifically turns on and off the electrostatic drivers, allowing the user to instantly compare the sound with and without them.



Non Audio stuff

For the design and the construction of the FX15, FiiO has cooperated with the famous HeyGears to create an earshell that is made using the advanced DLP-3D printing method with printing accuracy down to 0.0375mm. The material used is photosensitive resin, which features high impact resistance, providing robust protection for the electrostatic and balanced armature drivers.

The custom-like shape of the FX15 is like a triangle that not only feels comfortable to wear but also securely stays in the listener's ear and offers very good isolation thanks to the mildly extended nozzle. The FX15 is also very lightweight thus offering a great wearing experience that makes it suitable for long listening sessions. The appearance is unique with a design pattern at the faceplate that is beautiful and discreet looking at the same time. The FX15 is one of the most comfortable, beautiful looking and well made earphone FiiO has made up to date.

Cable

The cable of the FiiO FX15 is worthy of a flagship. A well made and easy to handle detachable cable with expanded MMCX connectors for greater connection stability and longevity. It is a high-purity silver cable with 224 total wires separated into 8 strands of 28 wires each. Each wire is independently insulated and the cable features Litz braiding and an outer sheath that is made of environmentally friendly TPU. Furthermore, the cable has interchangeable, twist-lock, 3.5mm and 4.4m plugs. You can find less thick and more lightweight flagship cables but this is a really good one.

Accessories

FiiO is always generous when it comes to the included accessories. The contents of the FX15 package are illustrated in the following photo.



Power requirements and associated gear

The FiiO FX15 (24Ω/103dB) is relatively easy to drive but it scales incredibly well as it has a class leading transparency and mirror-like fidelity that demand the use of high quality sources. If you like a warm sound signature then use a warmer source and vice versa, the FiiO FX15 will always make sure to mirror the unique sound characteristics of every source. For this review I have mostly used the FiiO M15S, EarMen Angel and iBasso DX320.

Audio stuff

The FiiO FX15 has amazing clarity, mirror-like fidelity, class leading transparency and is one of the most refined and resolving earphones that you can buy without reaching the kilobuck categories. The FiiO FX15 combines excellent technicalities with a musical and engaging sound signature that is aided by a balanced tuning that pays equal attention to all parts of the frequency range.

Sub-bass extension is fantastic, the FiiO FX15 doesn't have any problem at faithfully reproducing the first octave without overpowering the rest of the frequencies. The low-end is weighty, punchy and dynamic with realistic contrast and excellent layering. The texture is not that visceral but not lean either, the bass is tight and very fast so it can easily follow the speed of the electrostatic drivers while it is crystal clear, controlled and well defined. The upper bass is slightly emphasized but not that much as to become tonally inaccurate or to mess with mid-range clarity and presence. The feeling is slightly warm, you can use the balanced or bass ear-tips for a mid-bass focused sound, that is suitable for more casual and fun listening moments, or switch to the vocal or SpinFit ear-tips when you need a more neutral bass tuning for critical listening. For an even more neutral bass you can use the FiiO HS18 ear-tips but they will also make the sound too dry, lean and bright.

The mid-range really shines thanks to its tonal accuracy, the harmonic richness and its timbre realism. The FX15 is musical and engaging, the voices are slightly prominent and the instruments play a supportive role without losing their presence and identity. The FX15 might be using only one BA for reproducing the mid frequencies but it is surprisingly articulate, resolving and refined. The texture is just a bit lean but not dry and by no means clinical. The mid-range has a realistic tonality for both instruments and voices without exhibiting any balanced armature timbre. Tonal balance is good, there is an upper mid-range emphasis but not as much as to cause listener fatigue unless you are listening to poorly recorded material.

The treble is delicate, ethereal and refined like a carefully woven spider web that might look fragile at first but it is strong enough to withstand the furious weather elements. Such is the treble of the FX15 which is finely shaped and sleek but still powerful and crisp with solid extension, exemplary transparency and top-notch definition. Sparkling, energetic and airy, shed with sun-bright light but not sharp or piercing, neither harsh or rough and really absent of any metallic timbre.

These are high frequencies at their best, the FiiO FX15 is made for listeners that seek crystalline clarity, class leading expensiveness and deep detail retrieval but at the same time don't sympathize with analytical, overly bright and clinical sounding earphones. I don't like bright earphones but the FiiO FX15 has instantly become one of my favorites despite its undeniably emphasized treble. This is because it is so refined and ethereal that it gets impossible to sound bright or piercing.

FiiO has done an excellent job into driver implementation and succeeded in making sure that the delicate and ethereal sound of the electrostatic drivers never gets overshadowed by the mid and lower frequencies. At the same time, the four electrostatic drivers never act like a spoiled prima Donna who tries to steal the show but they rather work in perfect harmony with the rest, producing an extremely cohesive and homogeneous sound.

The FX15 is open and wide sounding without any traces of congestion. There is plenty of air and space around the performers, positioning accuracy and imaging are exceptional, depth layering is excellent and there is plenty of ambient information that contributes to the overall sense of immersiveness and realism. What happens though is that the presentation is rather intimate, the listener feels as if sitting too close to the performers and the soundstage is mildly lacking in holographic expansion and the feeling of grandness.

The FiiO FX15 is very enjoyable with all kinds of music, especially if you take advantage of the various ear-tips for fine tuning the sound. But the truth is that this set is tailor-made for critical listening to classical and acoustic music. The better the recording and the quality of the source, the better your listening experience will be as this is an earphone that scales incredibly well.

The tuning switch

This feature is rather useless unless you are curious to find out how the FX15 can sound when you mutilate its electrostatic drivers. Switch off the electrostatic drivers to transform the FX15 from a flagship into an earphone that might sound a little smoother and less sharp in the treble but also lacking in treble quality, tonal balance and cohesiveness. One possible situation for using the switch is for listening to really bad and harsh sounding recordings or when you have a hissing source.



Cable upgrade

You can further enhance the sonic performance of the FiiO FX15 with a simple cable upgrade. Readers will already know that I am a great admirer of the Lavricables pure silver cables that I regularly use for reviewing and music listening. The Lavricables Ultimate is a well made and beautiful looking cable with high quality plugs, a soft feeling and great handling. These are not reasons of course to make you swap the already excellent stock cable.

But you can consider trying a Lavricables Ultimate because, subjectively speaking, it slightly enhances the transparency of the FX15, it helps it sound even more natural and refined, especially in the treble, the timbre becomes more realistic and the bass gains in control and definition. The better your source, the more noticable the differences are going to be but still we are talking about subtle sonic enhancements so don't expect something spectacular. Cable upgrades are always the cherry at the top of the cake when the rest of your audio chain is perfectly matched.



Compared to the FiiO FH9

The FH9 is FiiO's previous flagship, a semi-open, hybrid earphone with a very large 13.6mm DD and 6BA. Too many drivers that need a larger housing so the titanium-made FiiO FH9 is bulkier and heavier than the FX15. The fit is still quite comfortable, despite the size, but it really can't match the supreme comfort of the FX15 which is also much more effective at blocking external noise.

The FiiO FH9 has a bass dominant sound signature but it also manages to stay tonally balanced and well defined throughout the whole frequency range. Thus said, the bass on the FX15 is slightly faster and more controlled, a bit faster and more refined with better layering but while it is powerful and dynamic enough, there is no way to match the sheer power, the thundering dynamics and raw impactful force of the FH9.

I find the FH9 as slightly more resolving and refined in the mid-range, the sound is fuller and weightier while tonal balance and timbre realism are more or less the same between the two earphones. The opposite applies for the treble and the higher frequencies where the FX15 is the undeniable champion. Not only is way more resolving and refined but it is also considerably more natural sounding without any traces of metallic timbre. It extends better, it is crispier and more energetic with greater definition and finer articulation.

The FiiO FH9 offers a wider and more expansive soundstage, the presentation is grander and more holographic. There is more free space and air around the performers but the FX15 is doing much better with ambient information and positioning accuracy so while it might not be that grand sounding, it is more immersive and communicative.

Conclusion

The FX15 is the most resolving, refined and mature sounding earphone FiiO has made up to date. This is a critical listening machine that still manages to stay musical and enjoyable with all kinds of music. A living example that frequency measurements don't always tell the truth. A seemingly bright earphone that doesn't sound bright or piercing at all and maintains an excellent sound balance throughout the whole frequency range without causing listening fatigue. The FX15 is the most expensive earphone ever made by FiiO but it still retains the company's unprecedable price to performance ratio. This is not the end of the road but someone must spend considerably more money to get something better than the FiiO FX15 which offers flagship level performance without the flagship price tag.

The review sample was kindly provided free of charge.

The price of the FiiO FX15 is $749 and you can buy it from FiiO.eu

Introduction

Drop has made some excellent collaborations during the past ten or so years and produced many, award winning, headphone amplifiers but all of them were solid state or tube hybrids. Thus Drop + xDuoo TA-84 is their first, all-tube headphone amplifier with an OTL topology.

Technical highlights

The amplifier is a collaboration between Drop and the Chinese manufacturer xDuoo who has a great expertise in the field of tube amplifiers. Drop + xDuoo TA-84 utilizes Output Transformerless (OTL) topology to manage signal without a transformer, greatly reducing distortion. For the preamp phase, it features dual ECC82 tubes and for the power amp phase, it runs dual EL84 pentodes.

The TA-84 utilizes xDuoo-designed capacitors in the power amp to do the job. They’re exceptionally quiet and impressively linear but since they’re outputting directly from the power tube, the output impedance of the amplifier is rather high, making it suitable for use with high impedance headphones from 100Ω and higher.

The Drop + xDuoo TA-84 is also equipped with a stepped potentiometer, which has 21 defined steps (each with a specific value of resistance) to help achieve unparalleled precision, reliability, and channel balance in output level. Paired with the gain switch at the back you can hit the perfect setting for your favorite pair of headphones or powered speakers. The difference between low and high gain is 16dB. The 21 steps are enough to allow every single step sufficient margin for fine adjusting the volume without loud jumps but the rotating action of the potentiometer is a little stiff and not smooth enough.

Furthermore the xDuoo TA-84 has an onboard USB DAC with one ES9018K2M DAC chip that supports input sampling rates up to 32bit/384kHz PCM and DSD256.

The xDuoo TA-84 has a preamplifier line output for both the line input and the onboard USB DAC. A very handy feature that allows you to experience tube sound with your favorite active monitors. Unfortunately the headphone and preamplifier outputs are simultaneously active and plugging a headphone will not mute the preamp.

Non Audio Stuff

The Drop + xDuoo TA-84 amplifier has an oblong, rectangular shape, measuring 26.8x16.3x11.6 cm, so it is quite tall but also narrow and compact enough to fit virtually anywhere as long as you have enough height clearance. The chassis has a full aluminum alloy construction with a smooth black finish and is exceptionally well made without sharp edges or corners.

The design is simple and minimalistic, this is a classic tube amplifier, the tubes are positioned at the front part and the power transformer is encapsulated in a box at the back. All four tubes are freely accessible and they are very easy to replace.

The front panel is plain and clean, the volume control knob is located at the center and underneath there is a status red LED and the 6.35mm headphone jack. Everything else is at the back; AC input plug, power on/off switch, voltage selector switch, USB type-C input, RCA line input, RCA preamp output as long as gain and input selector switches.

The amplifier has a soft start feature that allows about two minutes of tube warm time before it switches on. Operation is pretty simple, you can either use the line input with your favorite source or the onboard USB DAC without the need to install drivers.

Power output

The rated output power is 44mW/100Ω, 83mW/300Ω and 93mW/600Ω. These numbers might look low and underwhelming but don't pay attention. This is an OTL amplifier that produces the great voltage swing that is needed for driving high impedance headphones. The xDuoo TA-84 is very powerful when it comes to such loads and can drive all high impedance headphones without breaking a sweat.

I have tested the amplifier with the Sennheiser HD8XX (300Ω), Sennheiser HD660S2 (300Ω), Sennheiser HD650 (300Ω) and the iBasso SR3 (150Ω). The amplifier literally blew them away, it drove all of them with excellent dynamics and surplus of headroom at just ¼ of the volume range at the high gain setting.

The amplifier has a low noise floor, it is not dead silent but you have to raise the volume above middle to start listening to some tube hiss and transformer noise. There is no point in discussing the behavior with low impedance, high sensitivity headphones since the xDuoo TA-84 is not made for them.

Stock tubes

The stock ECC82 and EL84 tubes that are included in the package are from the Psvane classic series but they seem to be OEM made for bulk production without thorough quality inspection and any kind of matching.

Both the ECC82 tubes that came with the review sample were very microphonic and one of them was also defective as it produced heavy background hissing noise. The power tubes were good but in the end I have decided to replace all four of them.

Both types of tubes are quite common, they are currently produced by all known manufacturers and they are not too expensive. After checking prices and availability, I decided to order matched pairs of JJ Electronic tubes for both the ECC82 and EL84 variants.

After replacing the tubes, the amplifier became silent without producing background hiss or microphonic noise and worked just fine. Furthermore, the JJ EL84 power tubes proved to be more dynamic, controlled and technically potent than the stock ones so I suggest that you should do some tube rolling to get the most out of the amplifier.



Audio stuff

The sonic performance of the xDuoo TA-84 is really great, this is an amazing little amplifier with a favorable and immensely enjoyable sound character that combines plenty of tube magic with very competitive technicalities that are easily comparable with solid state amplifiers of the same category.

The sound is slightly warm, rich and harmonious with great musicality and an incredibly analog character. The timbre is natural, organic and realistic, all acoustic instruments and voices are reproduced with an extremely lifelike manner, the most colorful harmonies and varied overtones.

The xDuoo TA-84 amplifier has a modern way of thinking when it comes to its tube implementation. The audio circuit is designed as neutral as possible without adding much coloration to the sound or altering the linearity of the measured frequency response. This is not like some old tube amplifiers that used to mess with frequency response, mute the treble or boost the mids and the bass to make the music sound syrupy, warm, blurry, hazy and slow without much control and definition.

Technicalities are kept solid and very competitive, the xDuoo TA-84 is a neutral and linear sounding amplifier without compromising in treble extension and clarity. The sound is sparkling and energetic with great definition and excellent detail retrieval for such a type of an amplifier. The bass is fast, tight and controlled with good layering and the mid-range is spacious, present and well defined without any significant coloration.

So, someone would ask what's all the fuss about tubes? Well, what really happens is that the tubes have the ability to mostly enhance even harmonics throughout the whole frequency range, making for a pleasing and smooth sound with analog-like characteristics and plenty of musicality. They add extra weight to the low-end which is visceral and full bodied while maintaining great dynamics and physical impact. Full bodied and weighty are also the mid and higher frequencies so the sound is very cohesive without exhibiting any kind of weight loss in the treble. The decay is natural, the notes fade away in a timely manner, not too fast or too slow and are finely sculptured with a holographic relief.

There are solid state amplifiers of the same price category that are definitely more technical sounding, with better transparency and clarity, deeper detail retrieval and more impactful bass but none of them can match the inherent musicality, the harmonious nature and the music fluidity of the xDuoo TA-84.

No competitive solid state amplifier is as visceral and full sounding as the Drop + xDuoo TA-84 and only few of them can match the holographic properties of its soundstage. The soundstage is amazingly open and spacious, both expanded and deep with largish images. You can certainly find several solid state amplifiers that can surpass the xDuoo TA-84 in imaging precision and positioning accuracy but no one of them can sound more holographic and majestic.

The DAC

The onboard DAC is crystal clear, linear and transparent so it pairs well with the plethoric nature of the amplifier. Very good and satisfying performance to boot up or when funds are limited but honestly, the xDuoo TA-84 scales incredibly well and you are going to do much better with a high quality, external source.

Conclusion

The xDuoo TA-84 might be Drop’s first all-tube, OTL headphone amplifier but I think that is their best sounding product thus far. Musical, engaging and analog sounding, this is a great amplifier with competitive technicalities, great tube rolling potential and plenty of power to drive all high Z headphones. Well made and sturdy, with a high quality onboard DAC and preamplifier output, the Drop + xDuoo TA-84 represents an excellent value and is one of the best OTL amplifiers you can buy without the need to break the bank. Actually, given the current offerings in the market, you will have to spend at least double the money in order to get something marginally better than the xDuoo TA-84 so I would suggest you hurry and get one while it is still available.

The review sample was kindly provided free of charge.

The price of the amplifier is $399 and is exclusive available from Drop.

AUNE Yuki

The Aune Yuki is a portable USB DAC/amp with a detachable type-C cable and two headphone outputs, one 3.5mm and one 4.4mm balanced. The Yuki is equipped with dual CS43198 DAC chips in a balanced configuration with two independent channels for better dynamics and separation.

The uniqueness of the Yuki is that Aune has opted for a discrete headphone amplifier instead of using ready made op-amps. It is a 4-way balanced, headphone amplifier circuit with 4x4 transistors to drive the output. A total of 16 transistors that require a specially designed ±5V power supply.

Moreover, the Yuki utilizes a special, dual layer structure with independent PCBs for the digital and analog circuits. The PCBs are of hybrid ceramic compound that combines excellent thermal conductivity, low dielectric loss and high strength.

Non Audio Stuff

The Yuki is UAC 1.0/2.0 compatible and “plug ‘n play” for Mac, Android smartphones and DAPs. For Windows 10 or higher you can use it directly without installing any drivers but for high resolution bit-rate native PCM or DSD files playback on Windows, a driver and foobar 2000
are needed. The Yuki supports high resolution decoding up to 769kHz/32bit PCM and DSD256.

The Yuki has independent volume control and two gain settings, low and high, that can be selected by simultaneously pressing the two volume buttons for 2 seconds. A notification LED is missing so there is no way to display the selected gain or the input sampling rate.

The chassis is made from CNC aluminum alloy with a fine, baked painting, white finish. The front face has a glass window insert that allows a view of the PCB board with the transistors while at the back there are two small buttons for the volume adjustment. The Yuki has a unique appearance that is aesthetically pleasing and is also exceptionally well made.

The outer dimensions of the Yuki are 53.5x24x13mm, so it is not bigger than competitive devices, like the iBasso DC04PRO, while the weight is 26g, so it is just a little heavier.

Inside the package you are going to find a high quality USB type-C cable and a USB type-A adapter. A synthetic leather case in a green or orange color is available as an optional accessory for $15.



Audio Stuff

The maximum power output of the Aune Yuki is 2Vrms or 90mW/30Ω from the 3.5mm jack and 4Vrms or 160mW/30Ω from the 4.4mm. Lower gain will half the output voltage to 1V and 2V for each jack. Nothing too spectacular if we consider that the iBasso DC04PRO can do 280mW/32Ω and the FiiO KA5 265mW/32Ω. The positive is that the Yuki is dead silent and noise free in both gain settings.

The Yuki is more suitable for earphones or very sensitive headphones like the Aune AR5000 (28Ω/108dB) or the SIVGA Luan (38Ω/100dB). Driving other headphones is a bit challenging for Yuki. The sound is lacking in dynamics and it can become harsh and bright if you push the amplifier to its clipping limits.

The Yuki is the most analog and organic sounding DAC/amp of everything else I have reviewed with the same DAC chip configuration. Aune has designed a device that takes the crystal clear and transparent output of the DAC chip and transforms it into a feast of colorful harmonies and melodious notes that blend together to make the most musical and engaging sounding DAC of the category. The Yuki is pleasant, smooth and polite with a touch of warmness but it is not syrupy sweet or dark and it is definitely not lacking in extension and clarity, not in energy, airiness and sparkle.

Timbre realism is really impressive, the sound signature is extremely natural and lifelike without a hint of digital glare or treble harshness while it still remains technically competitive without loss of fidelity.

Give the Yuki some respect and use easy to drive earphones to discover that it is one of the most impactful and dynamic USB DAC dongles with a desktop-like performance. The bass is really amazing, thundering and imposing, also fast, tight and controlled with excellent layering and definition. The low-end is weighty, visceral and full bodied when most other competitive DACs sound rather lean and dry.

The same textural qualities also apply to the mid-range and the treble where the sound still remains full bodied and rounded without exhibiting any loss of weight while climbing higher at the frequency ladder. The Yuki is resolving and refined with great detail retrieval and although some of the competition fares better in these departments, with a more hi-fi sound, none of them can match the natural and spring-like music flow of the Yuki.

What is really more impressive than the amazing low-end performance and the unique timbral qualities of the Yuki is its vast soundstage that expands both horizontally and vertically to make for a very holographic soundscape never produced before from a USB DAC dongle of this category. The Yuki made all my earphones sound extremely open and spacious, the soundstage was grand and magnificent with great ambience information while imaging was kept solid and precise.

Conclusion

The Aune Yuki is really special, it is the most analog and organic sounding portable DAC of the category with a timbre realism that is usually reserved for more sophisticated desktop gear. Extremely musical and engaging with very competitive technicalities, it is highly recommended if you want a DAC that can make your music sound like real music but the recommendation applies only if you plan to use it with sensitive earphones.

The review sample was kindly provided free of charge.

You can buy it from Amazon

The S15 is the successor of the popular S12 PRO earphone. An updated version that features a third generation, 14.8mm planar dual chamber driver. To ensure smooth transitions between the octaves, LETSHUOER S15 employs a dual acoustic tube structure with filter crossover scheme. Furthermore, a 6mm passive filtering module outside the planar driver, which uses the in-house developed R-Sonic Dynamic Harmonic Technology, is used for positive filtering of sound energy through proprietary filters.

Non Audio stuff

The earshells of the S15 are made from a combination of 3D printed resin compound with CNC curved aluminum alloy faceplates. They are anatomically shaped and lightweight, offering a stable and very comfortable fit but the nozzle is too short so some of you might need double or triple flange ear-tips that are not included in the package.

Build quality is great but the appearance is rather dull, there is nothing attractive about it, the S15 is boring without the premium feeling to go along with the asking price.

The 1.2m long, 2-pin detachable cable is made from 216-strands of silver-plated monocrystalline copper. It is a modular design with interchangeable, 90⁰ angled plugs. The package includes 2.5mm, 3.5mm and 4.4mm plugs. This is a durable and well made cable with reinforced sheathing and minimal microphonic noise but it is rather thick and a little heavy.

The LETSHUOER S15 comes into a nice cardboard box with a bottom drawer that includes all the accessories. A water-resistant, rounded case made from plastic, two sets of ear-tips in three sizes each and the detachable cable along with the three plugs.



Audio stuff

With 30Ω impedance and 106dB of sensitivity, the S15 is rather easy to drive without needing special amplification. It scales well with some extra power and a competent USB DAC dongle will do the job perfectly fine. For this review I have mainly used the iBasso DC04PRO, Cayin RU-7 and FiiO M11S. As per usual practice, the LETSHUOER S15 was left playing music for about 80 hours before listening evaluation.

The LETSHUOER S15 is not made to impress with ultimate technicalities or some kind of a popular tuning. It is a balanced earphone with a fantastic and a bit laid back sound character that grows on you after a while to become an addition. Don't get fooled and start analyzing frequency response graphs, just close your eyes and immerse in your favorite music only to find out that the LETSHUOER S15 is extremely musical, engaging and natural sounding with special timbre realism. The music that reaches your ears is lifelike, harmonious and very colorful.

The bass is more than enough to offer great satisfaction with all kinds of music, from electronic to classical. Actually, the bass is masterfully tuned, it is mildly emphasized, not too prominent but not too linear either, it is tonally accurate and moreover it doesn't bleed into the mid-range or get muddy. This is a bass that sounds fun and critical at the same time. It is dynamic and impactful with good definition and layering. Tight, fast and controlled, full bodied, weighty and visceral without audible resonances. It might not be the most technical and transparent bass but it has a great sense of realism and power that competitive planar magnetic earphones will have a hard time to match.

The mid-range is present, harmonious and natural with just a little emphasis in the upper mids. There is no point in analyzing whether certain instruments or voices will stand at the front or the back of the mix. What matters the most is that everything is reproduced in a lifelike manner. Notes have plenty of weight and roundness around them, the S15 is resolving and refined with good clarity and definition. Instruments and voices are reproduced with realism, woodwinds sound like woodwinds, brass like brass and violins like violins, you get the point. This is an earphone able to extract all the diversity and the essence of the music making for a very addictive and unforgettable listening experience.

The treble is a great departure from the LETSHUOER S12 PRO with its mildly sharp and bright tuning. The treble on the S15 is toned down a little to make for a smoother, less edgy and more forgiving sound. This doesn't mean that the S15 is muted or short of extension and energy. This is not the most airy and luminous earphone but it is not lacking in either clarity and definition while it is very resolving. Detail retrieval is certainly good but this is not the most analytical and brilliant set of earphones. What really sets the S15 apart from some of the competition is the finesse of the texture as well as the naturalness of the timbre. Higher pitched instruments and voices sound weighty and full bodied without any kind of induced artificiality or metallic harshness.

The soundstage is wide and spacious with very satisfying separation and imaging. Nothing spectacular when it comes to depth layering or holography but still the presentation is grand and realistically proportional with a great sense of the ambience.

Conclusion

The LETSHUOER S15 are excellent sounding earphones with a very musical and engaging sound signature. With their latest earphones and namely their flagship, the Cadenza, and the entry level DZ4, LETSHUOER have proved that they are not afraid to break some eggs and part from the trend. Thankfully enough because together with the S15, they have made three excellent sounding earphones that combine solid technicalities with a great sense of musicality. Something difficult to find these days where most earphones are either trying to impress with stretched technicalities or are tuned using the same target curve that we are all supposed to like.

This is a very mature earphone made for listeners with trained ears who know to appreciate timbre realism and tonal balance more than anything else. The LETSHUOER S15 will make your music sound like real music again and become your daily addiction before you even know it.

The review sample was kindly provided free of charge.
A more comprehensive version of the review with selected comparisons is available in my website.

The R7 was FiiO's first all-in-one desktop device to combine a DAC, a headphone amplifier, a preamplifier and a media streamer with an LCD touch screen under the same hood. A multifunction, compact sized, device with multiple digital and analog connections and all the benefits of using the Android operating system exactly like you do in a DAP.

The FiiO R9, which builds on the success of the R7, is the new flagship media streamer with many updates over the R7.



Technical highlights

Gone is the single ES9068AS DAC decoder of the R7, the R9 features two pieces of the flagship ES9038PRO, a DAC chip that is featured in several other FiiO devices like the M17, K9 PRO ESS, M15S and Q7. FiiO engineers are very experienced with this chip and they have learned how to push its audio performance into new heights. Each DAC chip contains 8 independent D/A converters that are connected in parallel for a fully differential output.

Inside the R9 is the world’s first 8-channel THX AAA 788+ headphone amplifier design. These headphone amps, fed by a high-voltage power supply, are connected in parallel via 2×2 groups for a four-way fully balanced design, greatly enhancing transient performance. The comb-shaped heat sinks and optimized circuit layout dissipate heat efficiently, ensuring the R9 is capable of continuous and stable high-power output. The result is that the R9 is capable of outputting 7300mW per channel at 32Ω, 102% higher than that of R7.

The R9 has a five- stage, sophisticated audio architecture with carefully-crafted IV, LPF, gain, pre-amplification, and current expansion stages. An important part of the audio circuit is the OPA2211 op-amps, which are made through the silicon-germanium (SiGe) CMOS manufacturing process that ensures the chip's excellent performance.
The variable gain and variable power supply voltage design result in 5 levels of gain, allowing you to exactly dial in your desired listening volume.



Moreover, the R9 adopts the high performance and low latency XMOS 16-core XU316 that supports 768kHz/32bit and DSD512. According to the test from FiiO's lab, the latency in USB DAC mode is about 20-60ms. Then follows a 4th-generation phase locked FPGA with dual Femto-second crystal oscillators.

Built into the R9 is a new 40W low-noise, high-efficiency and long- lasting, industrial-grade switching power supply. The R9 can also be powered by an external DC power supply, like the FiiO PL50, allowing the user to pair the R9 with a high-performance linear power supply that offers its own sound. Additionally, when the R9 is paired with an external AC power supply, you can choose to enable the "Ground Lift" functionality to reduce crosstalk for purer sound.

The R9 features multi-stage, separate power supplies for the digital and analog portions of the circuit that are designed with many precision LDOs for secondary voltage stabilization.



HDMI ports

A major addition over the FiiO R7, is that R9 adopts an independent HDMI chipset that supports HDMI input, HDMI output and HDMI ARC. The picture output supports up to 4K 60Hz for high-resolution audio and high-definition visual experience. The introduction of HDMI extends the use of the R9 from the desktop to the living room.

Bluetooth

The R9 features the Qualcomm QCC5125 Bluetooth chip that supports LDAC, aptX Adaptive, aptX LL, aptX HD, aptX, AAC, SBC for Bluetooth reception and AAC, SBC, aptX, aptX HD, LDAC and LHDC for transmission.

Full technical specifications

Inputs and outputs

The FiiO R9 includes many analogue and digital inputs/outputs that allow it to function as an all-inclusive multimedia center.

Front connectors are 6.35mm, 4.4mm and 4-pin XLR headphone outputs. The package includes two dust covers to protect the connectors that are not frequently used.

Rear connectors are one XLR balanced and two sets of RCA line outputs, two coaxial outputs/inputs, one optical output, one optical input, HDMI in, HDMI ARC/output, USB and USB type-C ports. The USB port supports host, USB DAC input and USB audio output functions while the type-C port supports OTG function.

The R9 also includes a card reader, 100 Mbps LAN port and external DC input as long as a mains input plug and power on/off switch.



Remote controlling options

The FiiO R9 supports a variety of remote control modes.

You can use the FiiO Control application which has a rather limited functionality and allows mode selection, volume adjustment, track selection and a few other functions.

The FiiO Link, which is only available through the FiiO Music player, supports Android WiFi and Bluetooth controls and iOS Bluetooth control.

Additionally you can remote control the R9 via the Bluetooth RM3 remote control that is included as a standard.

The FiiO Cast application allows screen mirroring on cell phones but performance is sometimes lagging. Furthermore every time you switch to another application on your phone, the FiiO Cast will revert back to the home screen and you have to set everything from the beginning.

UPnP is not natively supported so the FiiO R9 is not recognized as a renderer by applications like BubbleUPnP.

UPnP

Thankfully there is a workaround for enabling global UPnP support. First thing you have to do is to install the paid version of the BubbleUPnP application at the FiiO R9. Then run it and select from the renderers menu the FiiO R9 as the local renderer output device. Then you have to install and run the BubbleUPnP on your phone or tablet. You will find that the FiiO R9 appears in the available renderers list.

Now you can use the BubbleUPnP interface to remote control the FiiO R9 and stream music from all your favorite music services and network or physically attached drives.

Design

The R9 also adopts a luxurious metal bicolor design with a mirror-polished metal section treated with 11 times of polishing and electroplating processes. The high-density metal body is more robust and stable, helping to effectively reduce deformation and minimize degradation in sound performance caused by vibrations. Additionally, the newly designed dynamic light bar combined with the dynamic RGB lights on knobs makes for a more attractive desktop setup. The lights will display a different color pattern according to the input sampling rate and can be configured or switched off through the menu.

The FiiO R9 is weightier and more robust than the R7, build quality is really excellent and flawless. The outer appearance is premium with a luxurious feeling. One thing of consideration though is that the mirror surfaces are fingerprint magnets that need regular cleaning.



User experience

The FiiO R9 features a gorgeous 6” (2160*1080) vertical (portrait) screen, which is easier to read and operate than that of the R7. It has better visibility and more vibrant colors, enhanced brightness and excellent response time. The screen supports double tap to wake and can be used in a landscape mode.

Combined with a powerful Snapdragon 660 processor, 4GB of DDR4 RAM, 64GB of ROM and the open Android 10 OS, the R9 is fast and responsive, offering a silky-smooth user experience. Operating the FiiO R9 is just like using your smartphone or DAP. You can freely install and use third-party streaming music and other apps without worrying about compatibility problems. During the period of the evaluation, the FiiO R9 performed one firmware update and the system never crashed. FiiO has promised to upgrade the Android OS to version 12 with a future firmware update, sometime during 2024.

The R9 offers global SRC bypass for bit-perfect music playback and additionally supports a 10 band dynamic EQ with global effect. I don't equalize so I am not that experienced with software equalizers and I haven't tested the functionality of the EQ.

Operating modes

The FiiO R9 supports the following operation modes that can be easily selected from the drop down menu or they appear in a menu when you press the multifunction volume button:

Android, pure music, USB DAC, Bluetooth receiver, AirPlay, Roon Ready, Coaxial/optical input, HDMI input and HDMI ARC.

You can use both the headphone and line outputs of the FiiO R9 in the following combinations that can be selected from the corresponding rotary knob:

Phone and pre out simultaneously working with adjustable volume, phone out only, pre out only with adjustable volume and line out only with fixed level.

Additionally you can enable the coaxial and optical outputs to connect the FiiO R9 in an external DAC.



Accessories

The package includes a lot of high quality accessories that are pictured below.



Headphone amplifier

As discussed earlier, the headphone amplifier of the FiiO R9 is very powerful and can do a maximum of 7.3W/32Ω continuously with a peak output voltage of 50Vp-p.
There are five gain settings available, Ultra high, Super high, High, Medium and Low with three different volume curves for excellent matching with various types of loads, from very sensitive IEMs to hard to drive planar magnetic headphones.

The amplifier is powerful enough for almost every headphone in the market. Ultra high gain in 90 steps out of 120 is plenty enough to drive the HIFIMAN Susvara with impressive dynamics and plenty of headroom while with every other headphone that I have tried, like the Meze Elite or the Focal Clear Mg, the R9 didn't break a sweat. Additionally, low gain is noise free and dead silent even with pretty sensitive earphones like the Soundz Avant. The single ended output is also powerful enough and will not have a problem driving many headphones that can't be converted into balanced.

Audio performance

Let's start with the DAC line output of the FiiO R9 which was tested fixed in a 2-channel system consisting of the Audio Physic Spark 6 speakers and the Kinki EX-M1 integrated amplifier in a dedicated listening room.

Make no mistake, the sound quality of the FiiO R9 as a DAC is of the highest standards, making the R9 suitable for use in demanding speaker and headphone systems. The performance is easily comparable with various standalone DACs of the same category, easily surpassing some of them in transparency, neutrality and technicalities.

I would never buy the FiiO R9 to pair it with entry level or mid range active monitors like the FiiO SP3. The R9 deserves to be paired with high quality active monitors or passive speakers and headphones.

Line out

The FiiO R9 offers impressive transparency and fidelity with crystalline clarity and outstanding definition. The frequency response is measured as absolutely linear but actual listening reveals slightly emphasized harmonics on the low-end which is perceived as a bit more present but not dominant.

The overall sound temperature of the R9 is not warm but not cool either, the texture doesn't have much of an organic or analogue like characteristics but it is definitely not clinical or sterile. This is the most mature and sophisticated implementation FiiO has done to the ES9038PRO so far. I think that performance is pushed to its boundaries and from this point on, it can't get any better without going the discrete route.

What FiiO has managed to do is to make the R9 sound absolutely transparent, with a mirror like fidelity and top tier technicalities, but at the same time largely vanishing the digital glare and annoying artificiality that are usually associated with this particular DAC chip. In this regard, the sound character of the R9 is neutral but with a natural timbre, the texture is lean but not dry, detail retrieval is astonishing but not fake and resolution hits master class levels.

The treble is alive, sparkling and energetic, slightly sharp but not bright or fatiguing, airy and luminous with excellent separation and definition. The R9 is not forgiving, it will definitely expose mediocre recordings but on the other hand, it is not ruthlessly revealing and punishing. As said earlier, the timbre is natural without digital artificiality. The texture is still rather lean but not leaner than in the lower frequencies and as such, higher pitched instruments don't sound thinner than their lower counterparts and never fade faster than the ideal. The texture is very refined, the sound is by no means coarse, edgy or rough.

The mid range is present, articulated and expressive with high levels of musicality. There is a holistic approach to the mids, they are not projected or emphasized more than the rest of the mix and are reproduced with equal gravity, leading in a very cohesive sound presentation. Separation, clarity and definition are exemplary, you can hear the faintest note, every breath and movement, very alive and lifelike listening experience. Harmonic variety is satisfying, the sound is colorful and harmonious but not as much as in competitive DACs with more sophisticated output stages.

The bass is strong, impactful and contrasted with excellent handling of sudden dynamic changes, from silence to climax and vice versa. This is a DAC that pairs well with dynamic amplifiers and will not bottleneck your system when it comes to low-end heft and punchiness. The bass is fast, tight and controlled with precise timing and exemplary layering. The texture is still lean, the bass is not that weighty and visceral but it never gets dry or skinny.

The R9 (both as a DAC and all-in-one) has a room (or head) filling soundstage which is truly expansive and tall with precisely focused and accurate images. The presentation is grand and magnificent but depth layering and ambient resonances could be better.

Headphone amplifier

The masterfully implemented THX amplification modules offer achromatic and transparent headphone amplification without adding or subtracting anything from the R9 sound signature as described above. What they do is to add plenty of headroom and great dynamic range with any of your favorite headphones. The supreme sound of the DAC is mirrored and transferred directly into your headphones without a single loss in quality and any further sonic interference from the amplifier. This translates into a magnificent listening experience as discussed above with deep respect to your headphones tonal characteristics and balance.

Selected comparisons

FiiO M17 & K9 PRO ESS

The FiiO M17 DAP and K9 PRO ESS desktop DAC/amp are also designed with dual ES9038PRO DAC chips and THX amplifiers. I am not going into a detailed side by side comparison because their general tonal characteristics are more or less the same. Furthermore, form factor and functionality speak for themselves so the question is whether the FiiO R9 justifies the price difference not only for the uniqueness of its design and connectivity but also for sound differences.

The answer is straight, the FiiO R9 is the most mature and sophisticated sounding of the three. The overall sound signature might be quite similar but the R9 punches a bit above the other two thanks for its more natural and realistic timbre, the lowered digital artificiality, the improved resolution, the finer textures, the greater dynamic range, the higher fidelity and the better sound cohesiveness.

FiiO R7

The same kind of findings regarding the sonic performance, to an even greater extent, apply when comparing the FiiO R9 vs the FiiO R7. Higher output power, enhanced dynamics, improved resolution and refinement, blacker background, grander and more expansive soundstage, better transparency, more natural and realistic timbre, much less artificiality and digital glare, all these differences justify the flagship status and the price difference between the two devices.



Additionally, the R9 has extra functions and connectivity options, it is better made and more premium looking, has larger and more vibrant screen while internal components and circuitry are upgraded.

Conclusion

The FiiO R9 is the most sophisticated and mature sounding audio device FiiO has designed up to date. They have pushed audio performance to its boundaries and it is rather impossible to extract more sound quality from the combination of the ES9038PRO DAC chips and the THX amplification modules.

Furthermore, the FiiO R9 is a versatile, all-inclusive wireless media streamer and DAC/amp with all possible combinations of inputs and outputs that is as easy and fun to use as your smartphone. It is compact enough to fit virtually anywhere, it is premium looking and very well made with high quality materials.

This is a minimalistic, high-end, swiss army knife, just add active speakers or headphones and let the music play. The only thing missing now from FiiO's vast catalog is a power amplifier for passive speakers but who knows what the future holds.

The FiiO R9 was kindly provided free of charge in exchange for an honest review.

The price is $1499 and you can order one from FiiO.eu

Intro

Everyone who is streaming music should be familiar with the Volumio OS as it is one of the most popular and widespread operating systems with thousands of installations in various streamers. Not only is it free to download and install but it is also used by many well known audio manufacturers as the basis for developing their own software.

Volumio Primo

Volumio is the company behind the Volumio OS and what most people don't know is that they also make their own streaming audio devices.

Volumio uses sophisticated hardware with high quality internal parts and the retail price of each product includes a lifetime subscription to the premium version of the Volumio OS as well as dedicated and personalized support.

The current product line consists of the Rivo (a dedicated steamer without internal DAC), the Integro (a steaming integrated amplifier) and the Primo (a streaming DAC). All three devices are designed and assembled by hand in Florence, Italy.

Technical

The Volumio Primo combines a music network streamer and a high quality DAC under the same hood. The decoding is assigned to a single ESS ES9038Q2M DAC chip in differential configuration connected in I2S to the digital input section for direct signal transmission in order to minimize jitter and noise. The internal board is neat and clean with short signal paths as you can see in the following photo.

At the heart of the Primo lies a highly performant quad-core processor, making Primo achieve first-class efficiency and speed for audio reproduction. The latest Amlogic Quad Core CPU is running at 1.9GHz and is combined with 2GB of fast DDR4 RAM to effortlessly run the Volumio OS.

I/O

Analogue audio outputs are available in both balanced XLR and single-ended RCA formats. There is also a digital SPDIF coaxial output to use the Primo as a standalone streamer to an external DAC plus one HDMI port for connecting an external monitor, two USB ports and a micro SD card reader.

Network connectivity includes Gigabit LAN port and wireless Wi-Fi 802.11a/b/g/n/ac with 2X2 MIMO antennas. Bluetooth 5.0 is also supported for convenience when the network is not available. WiFi and Bluetooth can be turned off when not in use in order to avoid causing electromagnetic interference to the wired connection.

Plenty of inputs and outputs but it would be even better if the Primo included a coaxial digital input for connecting a source like a CD transport. Some other competitive devices also come with a headphone amplifier but the truth is that none of them is as compact sized as the Primo.

The Primo is powered by an external switching power adapter (5V/3A) and strangely enough it doesn't have a power on/off button at the back so it is always in standby mode.

Appearance

The latest Red Dot Award winner, Design Narratives Ltd, has designed the Primo around a chassis made of high quality antimagnetic aluminum. The front panel has a classy dark wood texture and a power button at the center which has a status indicator LED that can be dimmed or switched off. The Volumio Primo is well made, beautiful looking and compact enough to fit nearly everywhere.

Operation

The Volumio Primo lets you stream from all favorite music services or bring content from local or network-attached drives and play internet radio. Most music services are embedded in the Volumio application, you just have to enter your credentials in order to gain full access to your content. The Volumio Primo is also Roon Ready certified, allowing seamless integration with Roon.

Native supported services are Airplay via Shairport Sync, Spotify & Spotify Connect, TIDAL & TIDAL Connect and QOBUZ. Available free plugins include Youtube, Squeezelite, Radio Paradise, Podcasts, Pandora, Fusion DSP, Roon Bridge, Soundcloud and Mixcloud.

The Volumio Primo supports bit-perfect playback up to 192kHz/24bit under all file types like DSD, WAV, FLAC, Alac, AAC, Vorbis, Cue, Mp3 and others. The Primo is also UPNP/DLNA renderer with open home support.

Setting up the Volumio Primo is an easy task, the only thing you have to do is to install the official Volumio application (available for both iOS and Android) and follow the on-screen instructions for wired or wireless connectivity. There is also the option to control the device via a browser or even connect it to an external monitor.

The Volumio OS is extremely stable, fast and easy to use with a well designed graphic interface. It regularly updates to fix minor issues and after two months of continuous use, it never crashed, not even a single time.

The Volumio app includes an AI-powered search function that searches content simultaneously in all active music services. Other notable features of the application include enabling/disabling the digital coaxial output, hardware or software volume control so you can use the Primo as a preamplifier, upsampling, a powerful DSP plug-in etc. Something missing though, is the ability to download and read the information PDF booklets that are available in Qobuz.

The Volumio premium OS allows full customization and personalization of the Primo with many useful options.



Audio Stuff

The Volumio Primo was tested as streamer and as all-in-one streamer and DAC both with headphones and in a 2-channel system.

The sound quality of the Volumio Primo is surprisingly good and far better than expected for the category. This is a DAC with great sonic performance that can rival much more expensive competitors by well established brands.

The Primo combines musicality and plenty of engagement with competitive technical performance. The sound is crystal clear and transparent, as expected from the ES9038Q2M DAC chip, with extension at both ends of the frequency range and mid-range transparency.

The bass is impactful and dynamic, tight and controlled with precise timing and great laying. It is not that full bodied and weighty, it is rather lean and maybe dry but it compensates with its very descriptive and well defined texture.

The mid-range has fluidity, richness and top class resolution. The timbre is natural and realistic with plenty of harmonic variety and good overall weight. The sound is not warm but not cool either, it is rather neutral with low digital artificiality. The user doesn't have the option to select one of the factory embedded digital filters of the chip but it seems that Volumio has done an excellent job in implementing their own one that sounds the most lifelike and natural.

The extended treble has a joyful, luminous and energetic character with top notch clarity and airiness. The high frequencies can sound a little sharp and a tad bright, depending on the recording, but by no means piercing, harsh or fatiguing. You can listen for hours long because of the finesse and the absence of harassing digital artifacts.

I have reviewed many DACs with single or dual ES9038Q2M DAC chips and the Primo is among the least clinical and artificial sounding. It has timbre and textural consistency from the deep lows up to the highs without exhibiting loss of coherency. It is not as technically proficient as some offerings by brands like SMSL or Topping but it is definitely more musical and less sterile.

The soundstage of the Primo is really glorious, especially if you upgrade the power supply, and this is something that gets very noticeable in a speaker system. It is dimensional and grand, open and spacious with sharp and accurate imaging. The sound reaches out of the speaker boundaries and the only thing that is lacking, when compared to higher-end offerings, is the relative lack of holography and the rather low communication of the recording ambience.

Conclusion

Volumio doesn't only make one of the best operating systems in the business but they also design really good sounding audio devices with streaming capabilities.

The Volumio Primo combines a powerful and easy to use streamer with a high quality DAC. Audio performance is really fantastic, far exceeding all expectations, thus making it an excellent all-in-one solution with an overall price to performance ratio that is hard to beat.

The Volumio Primo was loaned to me for the purpose of this review.

The price of the Volumio Primo is €799 and you can buy it from here.

More comprehensive version of the review is available in my website.

The FiiO FT5 is a full sized, open back planar magnetic headphone with a 90mm large-sized driver unit. This driver adopts a 6um ultra-thin diaphragm with a precisely crafted micron-plated aluminum silver alloy voice coil. The driver is produced using a nanoscale-level coating process for enhanced sound reproduction.

Technical specifications

Non Audio stuff

There is no plastic used in the FiiO FT5, the whole frame, the headband and the ear-cups are made from aluminum - magnesium alloy. The self-adjusting headband has an extra leatherette floating strap for better comfort.

The outer appearance of the FT5 is classic yet modern, it is more classy and luxurious looking than the FiiO FT3.

The FiiO FT5 is one of the best made and well constructed headphones, no matter the price.

The ear-pads of the FiiO FT5 have a larger inner diameter than that of the FiiO FT3 so they are much more roomy and comfortable. The weight of the FiiO FT5 is 456g and it gets evenly distributed thanks to the well designed headband. Additionally, the ear-cups have a 3-axis swiveling mechanism that allows them to freely rotate.

The overall feeling is that of a comfortable headphone that doesn't exercise much clamping force and is suitable for extended listening sessions. The only downside is that air circulation is not that great so the ears can become a little hot after a while.

The headphone comes with two types of ear-pads that are used to fine tune the sound. Suede and protein leather ear-pads. Pad swapping is easily done. The pleather pads are slightly more comfortable.

The FiiO FT5 comes with high quality, detachable cable with dual 3.5mm interface on the headphone side and interchangeable plugs. The package includes 3.5mm and 4.4mm plugs plus 6.35mm and 4-pin XLR adapters.

Except for the premium cable and the two different types of earpads, the FiiO FT5 is also equipped with a luxurious, leather storage case and a velvet carrying bag.



Audio stuff

With a 36Ω of impedance and a high sensitivity of 110dB/1Vrms@1kHz, the FiiO FT5 can be powered effortlessly by portable players and USB DACs but it also scales very well with desktop gear.

Taking the pleather pads as the reference point, the FiiO FT5 has a tuning with an extended low-end that is followed by a mildly subdued mid-range and present but non intrusive treble. Swapping to the suede pads will shift the tonal balance towards “V”-shape with a more prominent mid-bass while the rest of the frequency band remains pretty much unaffected.

The pleather pads offer a reference-style approach to the tuning of the low-end with very satisfying sub-bass extension and a bass that is just a little emphasized up to the lower mid-range. The bass is crystal clear and well defined with excellent transparency and layering. There is no hint of cup reverb or distortion, the bass is tight and controlled with fast recovery and natural decay. The texture is weighty and full bodied, almost visceral and the only thing that holds the performance a little back is the relative lack of physical impact and punchiness, at least when compared to the FT3 350Ω or more expensive planar headphones.

Despite some recession in the mid-range, the presentation is quite realistic with a mostly natural timbre, both when listening to vocal or instrumental music. This is not the headphone to use if you like prominent vocals because they do get pushed slightly back of the foreground. The texture is weighty and full bodied, the FT5 is a spacious and full sounding headphone while it is as resolving and refined as someone would expect from the category.

You can use the pleather pads to get extra transparency and definition, at the expense of body weight, or choose the suedes to add a touch of warmness and make the mid-range sound a bit fuller and more organic at the cost of clarity and definition.

The higher frequencies are bold, energetic and luminous sounding but without significant sharpness or harshness. The pleather pads will add greater transparency and extension to the treble, they will make it sound a touch crispier and more sparkling, maybe a tad bright, while the suedes will offer a smoother and more agreeable tuning with less sharpness.

Resolution is very satisfying for the category and so is the overall technical performance and the detail retrieval. The FiiO FT5 is not the most analytical and brilliant sounding headphone nor the most refined in the treble but it stands out for its natural timbre and the minimum amount of treble artificiality.

The sound of the FiiO FT5 is very cohesive, the notes appear with the same amount of thickness, all the way from the low-end to the treble, and they decay with the same speed.

The soundstage is exceptionally wide and spacious with excellent panning in the horizontal axis and surprisingly precise imaging that compares with more expensive headphones. Unfortunately the same can't be said of the depth which is lacking in layering, the soundstage is rather flat without much holography and grandness, while the listener feels as if sitting quite close to the performers.

The FiiO FT5 is a versatile and adaptable headphone that is suitable for listening to all kinds of music. You can use the pleather pads for more critical applications, when tonal accuracy, transparency and precision are desired or switch to the suede pads when you are in the mood for more fun and leisure moments or seek enhanced bass and
extra warmness.

Family business

The FT3 350Ω has deeper sub-bass extension and the most neutral tuning. Slightly bright and a bit clinical with a monitor-like character, is the most technical, transparent and crystal clear sounding of the bunch, with the most impactful bass but also drier and not as full bodied as the other two.

The FiiO FT3 32Ω has a smoother treble, a touch warmer mid-bass, authoritative bass and more present mids, a combination that makes it an excellent all-rounder headphone that is slightly lacking in resolution and refinement when compared to the FT5. The FT3 32Ω is a little more impactful and dynamic sounding in the bass but not that well defined and controlled as the FT5.

Both versions of the FT3 do not sound as wide and expanded as the FT5 but they compensate with deeper layering and a grander, more holographic soundstage.

Vs HIFIMAN Edition XS

The overall low-end response is very similar on both headphones but the Edition XS is tuned with less emphasis in the mid-bass and lower mid-range areas. The tuning of the XS is more neutral but with slightly recessed mids and a brighter treble. The Edition XS is a bit more transparent and clean sounding with better technicalities in the bass when it comes to definition and layering. It is also a tad faster and more controlled than the FT5 but not as impactful and dynamic while it is also drier and not as weighty or full bodied.

Vs HIFIMAN Sundara
The HIFIMAN Sundara has a more neutral, almost linear, bass tuning and considerably more present mids than the FT5 but is also brighter sounding. It is crispier and more energetic than the FT5 with better overall technicalities in the low-end but also drier, not as visceral and less impactful.

Conclusion
The FT5 is FiiO's first planar magnetic headphone and is a great one. Premium looking and exceptionally well made, it offers excellent sonic performance with very competitive technicalities at an affordable price, while it comes with one of the best accessory bundles in the market, no matter the price.

The FT5 is already more sophisticated and maturer sounding than its younger brothers. FiiO is progressing really fast, with great leaps ahead, in such a way to make us wonder what the near future holds for this innovative company.

The review sample was kindly provided free of charge in exchange for an honest review.

A More inclusive version of this review is available in my website.

The Sivga Nightingale is a planar magnetic earphone with a single 14.5mm, dual magnetic, driver. The dual magnetic field rectangular array structure features exceptional transmission sensitivity and impressive transient response. It leverages magnetic mechanics to thoughtfully pair two sets of high-performance rare earth iron boron magnets, resulting in a significant boost in efficiency compared to standard configurations.

Non Audio Stuff

The ear-shells are made from aluminum-magnesium alloy with a solid wooden faceplate that is hand polished to have a unique appearance as no plate is similar to another. The Nightingale is a well made earphone with a luxurious and unique appearance.

The ear-shells are quite compact and lightweight, their shape follows the natural contours of the ear and additionally the cable sockets are cleverly positioned in order not to interfere when wearing the earphones. The Nightingale is a super comfortable earphone that fits securely and stays stable without exercising any annoying pressure even after prolonged time of use. You wear it and then just forget about it, the only gripe is the average passive noise attenuation.

The well made cable uses silver plated copper wires in a four strand design. It is a 2-pin detachable cable with recessed connectors and a 4.4mm aluminum plug but the package doesn't include a 3.5mm adapter. The cable is lightweight and soft, yet durable, it doesn't get tangled and has minimum microphonic noise.

The package includes a hard carrying case with a side zipper and two sets of ear-tips in three sizes each that are stored inside a thin plastic case.



Audio Stuff

The rating of the Sivga Nightingale is 16Ω / 100dB so it is not that difficult to drive but the source must be able to provide plenty of current at such low impedance without clipping.

The Nightingale has a mildly warm, smooth and rather balanced tuning where the middle section stands out as the undisputable prima donna of the show.

Sub-bass extension is not that great for reproducing synthesized electronic tunes but enough for acoustic music where even the lowest notes are easily audible. The lower bass is slightly rolled-off until the mid-bass where things start to get even and linear. The mid-bass doesn't get emphasized, it is crystal clear, tonally accurate and without bleeding into the mid-range.

The low-end as a whole is fast, tight and controlled without audible distortion but not that crisp or firmly defined. There is a touch of echo and some lack in punch and dynamics, the attacks are rather soft, it is pretty obvious that the bass is intentionally tuned as the supporting actor to the glorious mid-range.

The mids sound present, crisp and well defined with excellent articulation and ample body. There is plenty of harmonic variety, the timbre is natural and realistic, voices and instruments sound alive, fresh and exciting with great emotional depth.

The mid-range of the Nightingale is really amazing, very engaging, lush and mildly warm with extra liquidity and without upper mid-range harshness.

The treble is also tuned in order to help the mid-range stand out so it is slightly truncated and not that extended as not to distract the listeners attention from the mids.

There is a certain lack of sparkle and excitement but not that much to make the Nightingale sound dark or missing in treble definition and clarity. This is a polite and smooth tuning that doesn't induce harshness and makes for a fatigue free listening experience.

The timbre is quite natural without any serious artificiality and devoid of metallic sharpness while texture is full bodied in accordance with the rest of the frequencies.

The Sivga Nightingale is a fairly open sounding earphone with sufficient width and adequate soundstage depth. Separation and imaging are more than satisfying for the category and the overall presentation is natural and proportional.

Conclusion

The Sivga Nightingale has a daring tuning that is not afraid to part from the current trend that favours “V” shaped and Harman based sound profiles. And this is a good thing in my book because not all people sympathize with these kinds of tunings and look for something different.

The Nightingale has a unique tonal balance with an amazing mid-range that is full of musicality and engagement. Vocal lovers are going to adore and appreciate the tuning of the Sivga Nightingale.

The review sample was kindly provided free of charge in exchange for an honest review.

The full review, including comparisons, is available in my website.

The Arya is one of the most famous HIFIMAN headphones and the first step towards the company's higher-end models. The Arya was first introduced back in 2018 and since then underwent two revisions, the V2 around 2020 and recently was equipped with the stealth magnets to become the Arya Stealth.

The Arya Organic uses the stealth magnets system but its diaphragm is thinner than the one found in the Arya Stealth.

Non Audio stuff

The Arya Organic is identical looking to the Stealth version except for the outside perimeter of the ear-cups that has a wood looking finish instead of plain black. A color pattern that is definitely more “organic” looking than the total black of the Stealth version.

The headphone is crafted using a combination of steel and high-quality plastic, striking a perfect balance between durability and lightweight design.

The suspension system, grills, and yokes are constructed from sturdy metal, while the ear cups are made from durable plastic. Both the metallic and plastic components surpass the Ananda in terms of quality. The metal is thinner and boasts a superior finish, contributing to an overall better construction.

During use, there are no annoying cracking noises to disrupt your audio experience. The height adjustment feature is effortless, and the suspended headband is made from synthetic leather with additional cushioning on the inner side for enhanced comfort. This part of the headband looks a little fragile and prone to tear and wear.

The Arya's build quality is exceptional, however there is still plenty of room for improvement in order to match competitive headphones in terms of craftsmanship and materials.

The Arya Stealth offers exceptional comfort with its spacious and adjustable ear cups, providing ample room for larger ears. The hybrid cushioned ear pads are not only soft to the touch but also allow for excellent breathability, ensuring a comfortable experience even after extended use.

Additionally, the headband effectively distributes the weight evenly across the head, eliminating any pressure points. The clamping force of the headphones is perfectly balanced, ensuring stability and a snug fit without causing any discomfort.

It's worth noting that the ear cups are quite large, and individuals with smaller heads may find the Arya to be too big, even at the lowest height setting.

Unfortunately no updates over the Arya Stealth regarding the quality of the included cable. It is a 1.5m long, entry level detachable cable with a dual 3.5mm interface and a 6.35mm plug, made from single crystalline copper with a cotton outer sheathing. At this price point a higher quality cable with a balanced plug and an adapter should definitely have been included.

There are no accessories included except a foam headphone stand. Strange enough considering that the much more inexpensive HIFIMAN Ananda Nano comes with a nice carrying case.



Audio stuff

Rated at 16Ω/94dB, the HIFIMAN Arya Organic is pretty easy to drive, even from portable sources as long as they can provide ample current at 16Ω loads without clipping.

Some portable USB DACs might run out of juice but the heavyweight champions, like the Cayin RU-7 and the iFi Go bar can do very well. The HIFIMAN Arya Organic is also DAP friendly, the FiiO M15S is an excellent match for them while they scale incredibly well with desktop gear like the HIFIMAN EF400 or the Goldenwave Serenade.

Have you ever wished for an Arya with more bass and a slightly warmer sound signature? If yes, you are lucky because it seems that HIFIMAN has been listening to user feedback and decided to make their dreams come true by making the Arya Organic.

The HIFIMAN Arya Organic is essentially the Arya Stealth with a more “organic” sound signature by adding a bit more bass and attenuating the presence region. Don't think about anything huge though, the tuning differences between the two headphones are really subtle but still enough to make the Arya Organic sound a bit warmer and more musical.

The Arya Organic has marginally better sub-bass extension than the Arya Stealth and just a touch more emphasized bass but the tuning is very linear and neutral without a single trace of mid-bass boosting or unwanted coloration. So the Arya Organic has a low-end that is more present and intense, however it still retains the same high quality characteristics and great tonal accuracy of the Stealth version.

The bass of the Arya Organic is fast, crystal clear, tight and controlled with excellent definition and layering while it sounds more dynamic and impactful than in the Arya Stealth. Furthermore it is less dry and lean with a weightier, fuller and more “organic” texture. A very successful tuning that makes the Arya Organic the perfect headphone for critical listening and at the same time considerably more enjoyable and fun during casual moments.

The mid-range is linear, neutral and essentially the same tuning with the Arya Stealth but comparatively, it has more fluidity and a sweeter, more musical tone. This is a very refined and transparent headphone with plenty of harmonic resolution, excellent definition of the finest micro details and a very realistic timbre. The upper mid-range has the typical HIFIMAN boost which favors higher pitched vocals and certain instrumental overtones. Nothing edgy though, the Organic version is slightly less rough, more refined and pleasant sounding than the Stealth and safer with lesser quality material.

The lower treble is smoother and more forgiving than the Stealth but still this is a bright headphone with an upper treble peak, exceptional luminosity and plenty of energy, however it is slightly less sharp and aggressive sounding than Stealth. The timbre is more realistic although not devoid of some artificiality in the highest notes. This is something that gets quite noticeable while listening to high pitched stringed and vented instruments or the upper top register of the harpsichord and the piano with a sound that is slightly dry, thin and metallic.

The overall timbre is improved over the Stealth, the notes feel weightier, the sound is more homogeneous and coherent, the overall feeling is that of a more natural sounding headphone that is more refined and resolving. Thus said, the Arya Stealth is a bit more transparent and technically competent with a crystalline, monitor-like character.

The Arya Stealth is famous for its soundstaging capabilities and one of the few headphones that can rival, or even better the Sennheiser HD800S. The Organic continues on the same path with a grand and holographic presentation, deep layering and excellent imaging with plenty of space around every individual performer. One notable difference between the Organic and the Stealth is that the presentation is now a bit less wide and more intimate as the listener is positioned a couple of rows closer to the stage but without compromising in focus and ambience information.

Conclusion

The Arya Organic is quite an achievement for HIFIMAN since they have managed to make an improved version of their most popular headphone which costs less than the launch price of its predecessor.

And I dare say that this is an improved version over the Stealth because it has a more balanced tuning with added bass, it is slightly warmer and musical, it resolves better, has extra refinement and presents the music in a more realistic and sophisticated manner.

In the end, this is one of the best value “high-end” headphones in the market, a cost effective way to taste great sound, especially if you favor transparency, definition and clarity with a slightly bright sound signature that doesn't forget about bass.

The review sample was kindly provided free of charge.

A More comprehensive review is available in my website.

The EM6L is the successor and an updated version of the much renowned SIMGOT EM5. It is a hybrid earphone which combines an 8mm, custom-designed, high-polymer diaphragm, dual-cavity dynamic driver to handle mid-to-low frequencies and two sets of balanced armature drivers to take charge of the mid-to-high and high frequencies. With meticulously set crossover points and precise tuning techniques the SIMGOT EM6L has been designed and tuned to adhere to the H-2019 Target Curve.

Non audio stuff

The ear-shells of the EM6L combine a black resin-compound main body with aluminum faceplate inserts that have a mirror-like finish that is elegant and beautiful but also a fingerprint magnet. The EM6L design is plain and minimalistic but with a luxurious appearance that is more premium looking than the price would suggest.

The low profile and lightweight earshells offer a stable and very comfortable fit that is ideal for extended listening sessions. Passive noise attenuation is also very satisfying.

The interchangeable cable is made from silver-plated copper wires and uses the 2-pin interface. The plugs are recessed so they attach more securely and minimize the risk of accidentally bending the pins. This is a well made cable that is soft, yet durable, and with minimal microphonic noise.

The package includes a compact carrying case and only one set of ear-tips in three sizes.



Audio stuff

The SIMGOT EM6L is pretty easy to drive (26Ω/119dB) and for this review I have mainly used the Shanling UA1 Plus and the iBasso DC03PRO.

The tuning of the SIMGOT EM6L is Harman based but with finer balance as it boasts ample bass extension but without subduing the mid-range that is followed by a smooth treble and non fatiguing treble.

The bass is deep and impactful with remarkable sub-bass extension. The tuning is not exactly neutral, there is a certain mid-bass emphasis that adds a cozy warmness to the sound and makes the EM6L suitable for listening to a great variety of bass heavy music. At the same time it manages to stay within acceptable tonal accuracy margins for reproducing acoustic bass instruments without too much unwanted coloration. The bass is weighty and full bodied and it doesn't bleed into the mid-range, it is clean and pretty well defined, with good layering for the category. It is quite fast in its recovery, tight and mostly controlled minus a touch of resonance that adds a little echo that shouldn't be there.

The mid-range is so engaging and musical sounding that you can't stop listening. Present, clean and well defined with great resolution for the category and a full bodied texture. The timbre is eminently natural and organic, full of colorful harmonies and great tonal realism. Voices and instruments are reproduced in a lifelike manner without any significant upper mid-range emphasis. The temperament is mildly warm and smooth but not too dark while the mid-range doesn't lack definition and transparency.

The smoothness extends right up to the treble which combines plenty of energy and airiness with a polite and easy going character. This is not the most extended or sparkling sounding earphone but it exhibits strong timbre realism and a lack of artificiality. The EM6L might not be the most detailed or analytical sounding earphone but it is not that sort of overall resolution.

The EM6L boasts very good timbre and texture consistency throughout the whole frequency range thanks to the excellent driver integration.

The soundstage impresses upon the first minutes of listening. It is unexpectedly holographic and grand, extending both to the horizontal and vertical axis. Surprisingly good layering for the category and a mostly accurate imagining but not with much air or blackness around the performers.

Conclusion

There is plenty to love in the SIMGOT EM6L, the balanced and easy going sound character, the strong and impactful bass, the lush mids, the smooth treble and the comfortable wearing experience. The SIMGOT EM6L is an affordable all-around earphone for everyday casual listening to all kinds of music that does most things right rather than wrong and it is truly pretty hard to dislike.

The SIMGOT EM6L was kindly provided free of charge in exchange for an honest review.

The Ananda Nano is the latest version of the popular HIFIMAN headphones, following the success of the Ananda in 2018. It retains the stealth magnets from the previous models, but now features a thinner diaphragm based on the renowned Susvara design. This new diaphragm offers improved sound quality with lower distortion, faster response, and enhanced dynamics and details.

For those unfamiliar with the HIFIMAN Stealth magnets, they have a unique shape that allows sound waves to pass through without causing any interference. This innovative design reduces wave diffraction turbulence, resulting in a more accurate and immersive audio experience.

With an impedance of 14Ω and a sensitivity of 94dB, the Ananda Nano is compatible with a wide range of portable audio sources. It is also the easiest to drive among all the Ananda models released so far. To provide a comparison, the Ananda Stealth is available in two versions: V2 with 26Ω/93dB and V3 with 16Ω/93dB.

Non Audio stuff

The new Ananda Nano looks almost the same as the Stealth version of the headphone, except for the ear-cups and connecting yoke which now have a sleek silver finish that matches the window-shaped grills. The ear-cups are still made of plastic, while the grills, holders, and outer part of the headband are made of metal.

The Ananda Nano has HIFIMAN's hybrid headband design, with a metallic upper frame and a leather strap that helps distribute the weight. The strap is black in color. In terms of weight, the Ananda Nano sits in between the lighter V3 (398g) and the heavier V2 (440g), weighing 419g. The detachable ear-cups are oval-shaped and asymmetrical, completely covering the ears without touching the inner mesh.

The Ananda Nano is lightweight and incredibly comfortable, thanks to its even weight distribution. However, it does have a slightly tight initial clamping force, and its large size may not provide the best fit for people with smaller heads, even at the minimum adjustment length.

The build quality of the Ananda Nano is typical of HIFIMAN headphones, with no significant changes from previous generations. It is a well-made headphone that appears to be durable, but the overall craftsmanship and materials used may not be on par with similarly priced headphones from other brands.



Power stuff

The HIFIMAN Ananda Nano is a breeze to power, just make sure you have a source with decent power output. Forget about the rumors of needing tons of power or excessive current, it's all urban legends. However, it does shine when paired with higher quality sources. Despite being a mid-range headphone, it's incredibly transparent and precise, capable of bringing out the best in high-end sources. Feel free to use your top tier ear, like the iBasso DX240, FiiO M17, EarMen Angel, Aune S9c Pro etc.

Audio stuff

The HIFIMAN Ananda Nano stands out for its exceptional transparency and ability to adapt to high-quality sources. It faithfully reproduces the audio without adding any personal touch, reflecting the true quality of the audio chain and recording. It has a revealing and unforgiving nature, requiring careful matching to meet your listening preferences.

In terms of frequency response, the Ananda Nano follows the typical HIFIMAN signature with balanced and neutral bass, a nearly linear mid-range, and slightly boosted treble.

The treble is sharp but it doesn't become overly bright unless your audio source is also bright. It's important not to mistake its energetic and sparkling nature for negative qualities like harshness or excessive brightness, as the Ananda Nano doesn't possess these traits. The headphone offers excellent treble extension, crystal-clear and highly detailed sound reproduction, surpassing expectations in resolution and refinement. It rivals more expensive headphones like the HIFIMAN Arya Stealth in terms of resolving power.

The overall sound is refined and articulate, capturing even the finest details within the recording and bringing the music to life. However, in the higher frequencies, there is a lean and dry texture, along with a hint of metallic timbre, particularly noticeable with acoustic instruments. It's not that the sound is out of tune or inaccurate, but at times, a touch of artificiality can be detected.

The mid-range of the HIFIMAN Ananda Nano is exceptional, offering transparency, clarity, and resolution. It provides an open and spacious sound with excellent definition and deep detail retrieval. Both voices and instruments are accurately reproduced with a realistic timbre and natural harmonics. The tuning is almost neutral and balanced, resulting in lifelike and tonally accurate sound. However, there is a slight emphasis on the upper-mids that may be bothersome for those with extra sensitivity in that area.

Despite its lean texture, the low-end of the Ananda Nano is punchy and impactful. It offers excellent dynamic contrast, although it may not sound as weighty or visceral. The sub-bass extension is great, and the bass is neutrally and linearly tuned without any mid-bass emphasis or coloring. The transition from the low-end to the mid-range is seamless, without any overlapping or bloating. The clarity remains phenomenal, and the bass is textured and well-defined. It is also agile, lightning-fast, and perfectly controlled even with demanding material. In summary, the HIFIMAN Ananda Nano delivers outstanding technical performance in the low-end.

The original Ananda was well-known for its expansive and open sound, and that reputation continues with the HIFIMAN Ananda Nano. These headphones have a wide soundstage that extends both horizontally and vertically, while still maintaining a strong center image focus. The imaging is precise, and the Nano excels at capturing subtle ambient details. The soundstage feels tall rather than deep, creating a grand yet intimate listening experience.

The HIFIMAN Ananda Nano is versatile and can be enjoyed with a wide range of music genres and personal preferences. While it may not be the best choice for EDM or classic rock songs with poor recordings, it shines with classical music, jazz, acoustic rock, and many other genres.

Vs Ananda Stealth

The HIFIMAN Ananda Stealth is similar to the Nano, but it has a slightly thicker diaphragm. It used to cost $999, but now you can buy it for as low as $399 from HIFIMAN's official store. The build quality, materials, and fit are the same as the Ananda Nano, except that the Stealth is completely black and doesn't come with a carrying case. The Nano is a little easier to drive, but nothing too extraordinary.

The sound of the Stealth and Nano versions of the Ananda is slightly different, but they both have a similar sonic character. The main distinction is that the Ananda Nano has a more powerful and dynamic bass, giving a fuller and weightier sound with stronger impact. The sound pressure levels are also more intense. In terms of frequency response, they sound more or less the same to me.

I think the Ananda Stealth is already a pretty fast and controlled headphone, but the Nano takes it up a notch. The Nano is more detailed and refined, with better transparency and fidelity. It also has a more crystalline and bright sound. On the other hand, the Stealth has a bit less emphasis on the upper-mids, giving it a warmer and more organic sound. The timbre realism is better and there's less artificiality in the treble. The Stealth also creates a more spacious and deep soundstage, while the Nano is more intimate and closer sounding, but with incredibly precise imaging.

In my opinion, the Ananda Stealth is still a great choice and hasn't been overshadowed by the technically superior Ananda Nano. Many people might prefer it not only for its slightly different sound signature, but also for its unbeatable price.

Conclusion

The HIFIMAN Ananda Nano is a fantastic option if you're looking for top-notch sound and improved technical features compared to previous Ananda models. And the best part? It comes at a slightly lower price, making it even more affordable. These headphones offer incredible value for their mid-range price range, delivering an audio performance that surpasses expectations.

The Ananda Nano was kindly provided free of charge in exchange for an honest review.

ISN NEO 5 Review

ISN Audio is an earphones brand exclusive to Penon Audio with many successful products like the ISN H30 and their flagship, the ISN EST50.

The ISN NEO 5 is a new hybrid earphone with 5 drivers per side. A 10mm dynamic driver for the low frequencies and 4 Knowles BA drivers for the mids and the highs.



Non Audio Stuff

The ISN NEO 5 ear-shells are made from medical grade resin in a semi-transparent purple color. They are anatomically shaped with a custom-like design following the natural curves or the ear.

The ear-shells are lightweight, durable and well made. The fit is tight and comfortable, you can wear them for hours without feeling annoyance and moreover they provide good passive noise attenuation.

Cable

The 1.2m long, 2-pin, detachable cable is made from single crystal copper silver-plated wires in a four strand design. It is a well made cable with high quality aluminum plugs that is durable, soft and free of microphonic noise. You can order the cable with either a 4.4mm, 2.5mm or 3.5mm plug, the review sample came with a 4.4mm balanced plug.



Accessories

The retail package includes a premium carrying case with a magnetic lid, three types of silicone ear-tips in three sizes each, a cleaning brush and a shirt clip.



Audio stuff

The impedance of the ISN NEO 5 is 26Ω and the sensitivity 110dB so we are talking about an earphone that is pretty easy to drive and at the same time quite immune to source noise.

With the FiiO M15S, low gain was more than enough while portable sources like the Cayin RU-7 or the iFi Go bar made them sing without much effort.

As per usual practice the ISN NEO 5 was left playing music for about 80 hours before listening evaluation.

You don't have to listen a lot in order to realize that the tuning of the ISN NEO 5 is emphasized towards bass. At the same time though, the mid-range is crystal clear and well defined, followed by a mildly smooth, but not that lacking in extension treble.

The low end gets the lion's share, it has a subwoofer-like extension and plenty of emphasis up to the lower mid-range. It isn't devoid of some mild bleeding but the overall impression is of a bass that it is not too overpowering over the rest of the frequencies thanks for the good driver coherency.

The bass is weighty, full bodied and visceral with great dynamics and physical impact. It is a mostly tight and well controlled bass but the recovery is not that fast while you can hear a mild echo.

The overall low-end balance is not that restrictive for listening to acoustic bass instruments however some of them, like the double bass and the cello sound rather colored and less accurate than they should be. Additionally there is a lack of definition and layering, especially during rapid bowing passages or when multiple instruments are playing together.

The mid-range is surprisingly crystal clear and transparent, with strong presence and not suppressed by the boosted low-end. The tuning is mostly balanced without any significant upper mid-range emphasis nor any notable recession. Voices and instruments sound smooth, well defined and articulated with plenty of harmonic variety and good timbre realism.

The treble is vibrant and energetic with ample extension, yet smooth, polite and mildly forgiving. Not the most analytical and sparkling earphone but still quite resolving and with the benefit that it never sounds fatiguing or bright. The treble has a rather weighty texture, it is not dry or lean, the timbre is good without any significant BA artificiality or metallic harshness.

The soundstage is wide and spacious with plenty of air around the performers who are accurately positioned in the horizontal plane. There is not much of a depth though the layering is nothing special and the presentation is quite intimate.



Compared to the ISN EST50

The ISN EST50 is the brand’s flagship earphone with a hybrid configuration consisting of 1 dynamic, 2 BA and 2 EST drivers per side. The physical appearance is the same as the NEO 5 and the ear-shells are identically shaped. The ISN EST 50 is slightly bulkier and a bit heavier than the NEO 5 which is marginally more comfortable.

Both earphones share a lot of similarities regarding their tuning. The bass is slightly less elevated in the ISN EST50 so it is a bit more correct and tonally accurate than the NEO 5. Technicalities are also better, the ISN EST50 is more tight and controlled, a little faster with better definition and less of reverberation.

The mid-range of the ISN NEO5 is more present and engaging with a fuller texture but the EST50 sounds more refined and resolving. The treble is smoother on the EST50 and maybe less energetic and extended but it is of higher quality and with greater timbre realism.

The soundstage of the ISN EST50 is wider, deeper and more holographic than in the NEO 5.

The ISN NEO 5 is actually a very good sounding earphone, especially if you prefer emphasized bass and present mids, but there is a good reason that the ISN EST50 is the flagship.

Conclusion

The ISN NEO 5 is a comfortable and well made earphone with an agreeable tuning that has plenty of bass and an easy going nature that makes it suitable for everyday listening of most kinds of music. It would not be my first choice for listening to classical music or jazz but it is really superb for electronic, rock and pop songs where it sounds very engaging and enjoyable with an inherent vibe.

The ISN NEO 5 was kindly provided free of charge in exchange for an honest review.

iFi NEO iDSD 2

The iFi NEO iDSD 2 is the upgraded version of the NEO iDSD, which received a lot of praise but had a few small problems. The NEO iDSD 2 comes with a bunch of new features and improvements compared to its predecessor.

This versatile device can be used in three different ways. Firstly, it can be connected to headphones as a Head-Fi DAC/Amp, providing an excellent audio experience. Secondly, it can function as a pure DAC when paired with integrated amplifiers. Lastly, it can serve as a DAC/Preamp for active speakers and power amplifiers, giving you even more flexibility in your audio setup.

More information

aptX lossless

The world's first DAC with the latest Bluetooth 5.4 chip is here! It supports the new aptX Lossless codec, which allows you to stream high-quality audio without any loss in sound. This DAC features Qualcomm's QCC518x Bluetooth audio chip, which is qualified for Bluetooth 5.4 and supports various Bluetooth formats like aptX Lossless, aptX Adaptive, aptX, LDAC, LHDC/HWA, AAC, and SBC.

However, it's important to note that currently, only a few phones support the new aptX Lossless codec. So, for most potential buyers, this feature may not be very useful.

But don't worry, the iFi NEO iDSD 2 makes up for it with its excellent Bluetooth reception. It supports LDAC and aptX HD codecs, providing a sound quality that is almost as good as a wired connection.

Non audio stuff

The iFi NEO iDSD 2 now includes a 3.5mm line input, allowing you to use it as a dedicated headphone amplifier with an external analog source such as a phono. Another exciting addition is the support for external clock via the 10MHz BNC input, ensuring even more precise clock signal accuracy. The LCD screen has been upgraded to a vibrant 2-inch color display that automatically adjusts its orientation to match the unit. Additionally, the iFi NEO iDSD 2 comes with a sleek new remote control made from aluminum.

The iFi NEO iDSD 2 has a sleek front panel that features an LCD display, a versatile volume control, and four buttons for various functions like input selection and gain settings. It also has a power button and two headphone outputs (4.4mm and 6.35mm) for your convenience.

On the back side, you'll find the XLR and RCA stereo analogue outputs, a 3.5mm line input, and digital inputs including coaxial, optical, and USB. There's also an external clock and DC inputs.

To power the iFi NEO iDSD 2, you can use the 9V iFi iPower2 power adapter that comes with it. However, it's worth noting that it can also handle input voltages of up to 15V.

Headphone amplifier

The original iFi NEO iDSD had a weak headphone amplifier that wasn't suitable for demanding loads. However, in the iFi NEO iDSD 2, they have made significant improvements by integrating the Diablo headphone circuit. As a result, the headphone output power of the NEO iDSD 2 is now 5 times more powerful than its predecessor. It can effortlessly drive a wide range of headphones, except for extremely difficult ones like the HIFIMAN Susvara.

I've personally tested the iFi NEO iDSD 2 with various headphones such as the Focal Clear Mg, HIFIMAN Ananda Nano, Sennheiser HD660S2, and iBasso SR3. It did an amazing job driving them, providing plenty of headroom and excellent control.

Additionally, the iFi NEO iDSD 2 comes with Auto iEMatch, which reduces hiss from high-sensitivity earphones without compromising dynamic range. It also offers four gain settings, allowing for better adaptability to different headphone loads. I even tested the background noise with the Soundz Avant, and I can confidently say that the device is completely silent and free from any noise.



Audio stuff

When I first checked out the original NEO iDSD, I was blown away by how transparent and neutral it sounded. It had a sleek and crisp texture, and the treble was unexpectedly vibrant for an iFi DAC.

The iFi NEO iDSD 2 takes a step back to its roots, bringing back the classic iFi sound signature that is warmer and more organic. However, it still maintains its fidelity, clarity, and extension across the frequency spectrum. While it may not be as technical or neutral as its predecessor, it offers a more analog and organic timbre with vibrant harmonies and overtones.

The NEO iDSD 2 presents a realistic and lifelike sound, with a full-bodied and visceral experience that maintains tonal accuracy and avoids any artificial digital sound. The treble is natural and luminous, lacking sharpness or excessive brightness, yet still energetic and honest. While it excels in detail retrieval, it doesn't have the same analytical or magnifying quality as the original.

The new amplifier section enhances the bass, giving it a powerful impact and dynamic punch. The bass is fast, controlled, and well-defined, with excellent layering.

The mid-range in the NEO iDSD 2 is simply amazing. It's not only fluid and musical, but also captivating, thrilling, and expressive. When you listen to voices and instruments, they come to life in a realistic way, with a refined and weighty texture that's full of detail. It's that signature iFi sound that we all adore, with its natural and human-like tone.

And that's not all, the soundstage in the NEO iDSD 2 is even more impressive than before. It's not just expansive, but also layered and holographic, giving you a truly immersive experience. While the previous model may have been slightly more precise in imaging, the new one takes it to another level by placing the performers in a spherical and vertical manner. It's like being right there with them.

Conclusion

The iFi NEO iDSD 2 is a game-changer compared to its predecessor. It boasts a better headphone amplifier stage and a bunch of new features. Not only does this DAC have impressive technical capabilities, but it also delivers a more refined and melodic sound.

For those on a budget who don't want to compromise on sound quality or features, the iFi NEO iDSD 2 is the perfect all-in-one solution. It's also a worthwhile upgrade for previous model owners, unless they prefer a more technical sound or have headphones with a darker tone.

There's really nothing negative to say about the iFi NEO iDSD 2. It easily stands out as one of the best and most affordable all-in-one DAC/amps in the sub $1K category.

The iFi NEO iDSD 2 was provided as a loan and now is returned back

A more comprehensive version of the review is available in my website.

Aune Audio S17 Pro

The Aune S17 Pro is a pure Class A headphone amplifier that is completely discrete and balanced. It utilizes twin JFET, a type of transistor known for its high input impedance and warm sound similar to a vacuum tube. This makes it perfect for a headphone amplifier. In the final output stage, the S17 Pro employs two pairs of output transistors per phase arranged in parallel. With a total of 16 output transistors, it can deliver a maximum power output of 7.5W per channel.

Full technical specifications

The Aune S17 Pro comes with a unique feature that lets you choose between two levels of quiescent current. You have the option to go for either 50mA or 100mA per transistor. Since each channel of the S17 Pro has two pairs of transistors in parallel, the actual quiescent current for each channel can go as high as 100mA or 200mA respectively.

The Aune S17 Pro comes with a cool feature that constantly monitors the temperature of the amplifier and shows it on the LCD display. This nifty feature is located in the lower right corner of the display. When the temperature reaches 69⁰C, the auto protection circuit kicks in and switches the bias current from 100mA to 50mA.

To ensure the Aune S17 Pro delivers top-notch performance and the best sound quality, it's crucial to maintain thermal stability in the output transistors. When you power on the amplifier, the temperature will match the environment, let's say around 22⁰C, and then gradually increase. It takes roughly 30 minutes for the temperature to stabilize at around 45⁰C for the 50mA bias and 55⁰C for the 100mA bias. Once it reaches this point, the temperature remains relatively steady and only rises when you start playing music.

For optimal performance, it's highly recommended to let the amplifier stabilize at the mentioned temperature values before diving into your music. So, power it on and give it at least 30 minutes to settle before enjoying your favorite tunes.



Non Audio stuff

The S17 Pro has Aune's signature ark design, which is both beautiful and minimalistic. However, one downside is that when you stack two similar devices, there are visible gaps on the sides.

The chassis is made entirely of CNC machined aluminum, providing effective EMI shielding. It has a sleek finish and comes in silver and black options. The multifunctional knob, also made of aluminum, feels smooth and sturdy without any wobbling. Overall, the Aune is a luxurious and well-crafted product that surpasses its price in terms of quality.

The front panel is simple and plain, with the LCD display in the center, headphone outputs on the left side, and the multifunction knob on the right. On the back, you'll find line inputs and outputs, available in both XLR and RCA plugs, as well as the AC mains input and power switch.

The Aune S17 Pro is a versatile device that serves as both a headphone amplifier and a preamplifier. It offers three different headphone outputs (4-pin XLR, 4.4mm, and 6.35mm) as well as line level inputs/outputs (XLR and RCA).

You have the option to control the device using either the multifunctional knob or the slim aluminum remote control that comes with it. The large LCD screen conveniently displays all the necessary information at once, although the colors may appear a bit washed out, especially the red one that indicates the 100mA bias operation.

Unfortunately, there is no option to dim or switch off the LCD screen.

The device provides several functions such as selecting between XLR or RCA line inputs, adjusting the gain to high or low, and selecting the bias current.

One thing to note is that the preamplifier output is always active and doesn't mute when you plug in your headphones. This means you need to be cautious not to accidentally damage your headphones if the volume control is set too high. This can be a bit inconvenient if you frequently switch between headphones or active monitors.

Audio stuff

The Aune S17 Pro is a prime example of an audio component that is finely tuned like a genuine instrument. It's not just about reproducing sounds, but about creating an immersive musical experience that is far from clinical and sterile. With this exceptional amplifier, the music effortlessly flows, captivating your senses and keeping you engaged. It's addictive in the best way possible, consuming your free time with soul-stirring and exhilarating music.

What sets the Aune S17 Pro apart is its stellar sound quality, combining technical excellence and transparency with a natural timbre that is unmatched. The timbre is the key to its audio performance, giving music a lifelike quality that is truly organic. Pair it with high-quality sources and headphones like the Meze Elite, and you'll experience music like never before. Yes, even the $4K Meze Elite sounds incredible with the $700 Aune S17 Pro, proving that this mid-priced amplifier can do justice to high-end equipment.

From the lowest bass to the highest treble, the sound produced by the Aune S17 Pro is rich, full, and harmonious. Its frequency response is linear, with a weighty and impactful bass that adds depth to your listening experience. The dynamic contrast is impressive, with excellent control and a well-defined, layered sound that offers clarity and resolution.

The mid-range of this solid state amplifier is simply amazing. It has a sweet and organic sound that is usually only achieved with vacuum tubes. It's warm, but not too mellow or dark. It's clear, defined, and offers a touch of magic. When it comes to instruments and voices, they sound incredibly lifelike and full, with a solid foundation and beautiful overtones. The mid-range is robust, spacious, and refined, making it perfect for all types of music, especially those with acoustic instruments and human voices.

The treble, on the other hand, is full-bodied and smooth. It's polite, yet still has great extension and clarity. It's energetic, but not overly nervous, and has a luminous quality without being too brilliant. You can listen to it for hours without feeling any harshness or fatigue. It's pure and realistic, with no artificiality or digital ringing, and it has a natural and effortless decay. The amplifier also excels at detail retrieval, bringing out all the hidden nuances in the recording without sounding too analytical or mechanical.

The Aune S17 Pro is known for its wide and spacious soundstage, offering excellent positioning accuracy and impressive depth layering. However, it doesn't necessarily outshine other competing amplifiers in these aspects. Nevertheless, its greatest strength lies in its ability to deliver a grand, immersive, and holographic sound experience. The amplifier produces large, well-defined images that seem to extend beyond the listener's head.

One of the remarkable features of the Aune S17 Pro is its compatibility with various sources and headphones. Whether you're using it with a smartphone, computer, or any other device, this amplifier pairs exceptionally well. While it can handle any genre of music with ease, it truly shines when it comes to classical music. The Aune S17 Pro brings out the intricate details and nuances of classical compositions, making it an absolute delight for classical music enthusiasts.

Conclusion

In simple terms, the Aune S17 Pro is a complete surprise. It's a headphone amplifier that combines all the technical skills of a modern solid state amplifier with a lot of musicality and realism. The sound it produces is incredible, making your headphones shine and allowing your music to flow like never before.

Don't be fooled by the price though, the Aune S17 Pro is one of the best solid state headphone amplifiers you can buy, and it can only be surpassed by competitors that cost two or three times more. In fact, it can easily be considered an end-game amplifier, no matter how expensive your sources and headphones are. Aune Audio has achieved something truly remarkable, setting a high standard for quality that will require a lot of hard work to surpass.

You can buy the Aune Audio S17 Pro from here.

A much more detailed version of this review, including comparisons, is available in my website.

HarmonicDyne Zeus Elite

The Zeus Elite has undergone enhancements and advancements compared to its predecessor, the Zeus. One notable improvement is the incorporation of a 50mm long-stroke layered diaphragm, consisting of two layers of inert composite film sheets held together by a layer of acoustic adhesive. This arrangement ensures stability for the membrane. Additionally, the diaphragm is complemented by an ultralight Japanese Daichi CCAW premium voice coil.
This sandwich configuration guarantees a more consistent distribution of vibrations throughout the membrane, minimizing distortions that may arise from fragmented reverberations. This linear functionality improves the sound's clarity and definition, while also enabling a wider dynamic range.

Non audio stuff

The headphone is crafted using a blend of wood, metal, and predominantly plastic components. The ear-cups are fashioned from dark Zebra wood and feature aluminum alloy protective grills adorned with an intricately engraved pattern, lending them a visually appealing appearance.

The remaining parts of the headphone are constructed from sturdy plastic, although they may not exude a high-end aesthetic. The inner frame of the headband is reinforced with a stainless steel sheet, enhancing its durability.

While the materials employed and the overall sensation of the Zeus Elite may not be considered truly "Elite," there is still potential for enhancement.

The headphone has a weight of 360g, making it lightweight and comfortable. It also has a medium clamping force, providing enough stability when worn on the head. The headband is equipped with a generous layer of soft padding, ensuring additional comfort. However, it is worth noting that the weight is not evenly distributed and tends to concentrate at the top of the head, potentially causing discomfort after extended use. The ear pads, which can be easily replaced by the user, are soft and well-cushioned with thick memory foam. Unfortunately, the inner space of the ear cups may not be sufficient for larger ears. Despite these minor issues, the HarmonicDyne Zeus Elite headphone overall offers a mostly comfortable and lightweight experience.

The HarmonicDyne Zeus Elite is equipped with two high-quality custom cables that are crafted using a blend of single crystal copper and silver-plated copper wires, resulting in a more harmonized audio experience. The cable connection system features a 3.5mm plug interface, allowing for effortless cable swaps.

Both cables are designed with balanced plugs, with one featuring a 4-pin XLR connector and the other a 4.4mm connector. However, it is worth noting that a 6.35mm adapter is not included, which means that using the headphones with single-ended sources would require purchasing an aftermarket cable or adapter.

The cables themselves are exceptionally well-crafted, boasting a robust and durable construction that minimizes any unwanted noise. However, it is important to consider that they are also quite weighty and may not be the most practical choice for portable usage.



Audio stuff

The HarmonicDyne Zeus Elite has an impedance of 32Ω at 1KHz and a sensitivity of 105dB/Vrms at 1KHz, making it effortless to drive without significant power demands.

The Zeus Elite offers a well-balanced tuning that showcases impressive bass presence, extending smoothly into the lower frequencies. The low-end is clear and distinct, with minimal emphasis on mid-bass and no bleeding into the mid-range. The tonality is remarkably natural, allowing most instruments to sound realistic without any excessive coloration.

This headphone delivers a highly impactful and dynamic sound, with minimal reverb within the ear cups. The bass is fast, tight, and controlled, although it may not be the most layered. Nevertheless, the bass line is well-resolved, avoiding the perception of sounding monotonous.

The mid-range bears resemblance to the Sennheiser HD650, although it falls slightly short in terms of resolution and refinement. However, the tuning is quite similar, featuring prominent mids and a subtle emphasis on upper-mids, which adds extra bite to certain voices and instruments. The Zeus Elite offers ample clarity and harmonic resolution, resulting in a natural and realistic overall timbre, complemented by excellent layering and definition.

The treble of the Zeus Elite is reminiscent of the Sennheiser HD650, but it lacks the same level of energy and sparkle. However, it still manages to maintain a smooth and polite sound signature, with enough light and clarity in the higher frequencies. These higher frequencies sound natural and forgiving. In comparison to the HD650, the Zeus Elite does lack some refinement, as the higher frequencies have a slight roughness to their texture and a comparative lack of resolution. Additionally, the fine-detail retrieval is not as deep.

The Zeus Elite by HarmonicDyne surpasses the Sennheiser HD650 in terms of its open sound and spaciousness. Its soundstage is remarkably wide and expansive, resembling that of a grand speaker. The headphone excels in depth layering, accurate positioning, and effectively conveying the ambient atmosphere, setting it apart from its competitors.

The HarmonicDyne Zeus Elite can be likened to the Sennheiser HD650 on steroids in terms of its exceptional low-end extension, dynamics, and soundstage. However, it may not possess the same level of resolution and refinement. This headphone excels across various music genres, ranging from pop and rock to grand symphonic and choral compositions. It provides an immersive listening experience, characterized by a delightful musicality and a pleasant touch of warmth and politeness.

Conclusion

The HarmonicDyne Zeus Elite is a solid headphone that can definitely compete with other popular options out there.

It has a similar vibe to the Sennheiser HD650, although it may not have the same level of refinement and detail. However, it makes up for it by offering impressive bass extension and a spacious soundstage.

The Zeus Elite boasts a well-balanced sound signature with a noticeable emphasis on bass. This combination creates an immersive listening experience that is complemented by its impressive technical capabilities. While the build quality could use some improvement, it is worth noting that the headphone is lightweight and comes with two high-quality cables and a convenient carrying briefcase. All of this is offered at a very competitive price point.

The HarmonicDyne Zeus Elite is available from Linsoul.

SMSL D6S

SMSL is a well-known audio brand from China that specializes in designing amplifiers, headphone amplifiers, and DACs. They are known for being fast and among the first in the industry to use the newest DAC chips in their products. One of their products, the SMSL D6S, is a standalone DAC that features the brand new ESS ES9039Q2M DAC chip. This chip is an updated version of the widely used ES9038Q2M found in many DACs worldwide.

The upgraded ES9039Q2M chip utilizes the HyperStream IV architecture, which improves performance compared to the previous HyperStream II. It boasts improved measurements, with a dynamic range (DNR) of 130dB and total harmonic distortion (THD) of -126dB.

In addition to the advanced DAC chip, the SMSL D6S incorporates four high-end OPA1612 op-amps in the balanced analog stage. It also features a third-generation XMOS XU-316 receiver, which supports PCM up to 32 bit/768 Hz, DSD 512, and full MQA decoding.

Furthermore, the circuit includes a separate audio clock and a built-in low-noise switching power supply with separate rails for the analog and digital stages. These features contribute to the overall performance and audio quality of the SMSL D6S DAC.



Non audio stuff

The SMSL D6S is a versatile audio device with three digital inputs (USB type-C, Coaxial, and optical) and two analogue outputs (XLR and RCA). It also supports wireless Bluetooth connectivity with high-resolution codecs.

In terms of design and build quality, the SMSL D6S features a modern and contemporary look, distinguishing itself from previous generation products. The device has a rectangular panel that houses the LCD display, giving it a unique appearance. The full aluminum chassis is well-made and finished, ensuring excellent build quality.

Operation of the SMSL D6S is user-friendly, with options to control the device using the multifunction knob or the included remote control. The analogue output signal is variable and can be adjusted from 0 to 99 for the full scale. This allows for compatibility with various power amplifiers and active monitors.

Additionally, users can select the desired digital input or Bluetooth reception, adjust the brightness of the LCD display, and choose the digital filter and DPLL level. During playback, the LCD screen only displays the input sampling rate, providing a clear and focused interface.

Audio stuff

The SMSL D6S was tested with various headphone amplifiers including the DROP + SMSL HO150X, Aune S17 Pro, and Violectric V222. The headphones used for testing were the Focal Clear Mg, iBasso SR3, and HIFIMAN Edition XS. All headphone cables used were made by Lavricables. Prior to the listening evaluation, the device was left playing music for approximately 80 hours.

The SMSL D6S is a highly neutral and transparent DAC with excellent fidelity. It converts digital signals to analog without any coloration or intervention. The device has a black and silent background, providing crystal clear sound with detailed retrieval and definition across the frequency range. While slightly analytical and lean in texture, it is not clinical or sterile sounding. The dynamic range is impressive, with impactful and contrasted bass, linear frequency response, and energetic treble. The sound is neutral, bright, and bold with rapid transients, but not harsh or fatiguing. The soundstage is wide and spacious with pinpoint imaging, although depth and holography may not be as pronounced. The SMSL D6S is ideal for studio production and can easily be integrated into various audio chains without altering the sound.

The Bluetooth connection provided by the SMSL D6S is not only fast, reliable, and stable, but it also maintains its performance within a working distance of 5-6 meters. The sound quality of this device is exceptional, although it does exhibit some common Bluetooth issues such as a slight lack of refinement and resolution, a slightly harsher and grainier treble, and a touch of artificiality.

When comparing the SMSL D6S to previous generation SMSL DACs that utilized the ES9038Q2M chip, like the SMSL DO100, it must be noted that there are no significant sonic differences. However, the D6S does offer a slight improvement in transparency, dynamic contrast, cleanliness, and technical proficiency. Apart from these minor enhancements, the sound signature remains largely unchanged. Therefore, if you already own the SMSL DO100 or another ES9038Q2M DAC by SMSL, upgrading to the D6S may not be worth it. However, if you are in the market for a new DAC, the D6S is a worthwhile purchase as it offers marginal improvements and incorporates the latest DAC chip.

Conclusion

The SMSL D6S offers exceptional transparency and linearity at an affordable price, along with an enhanced dynamic range compared to its predecessors. If you are in search of a DAC that delivers impeccable technical performance, a completely neutral sound signature, and a wide range of connectivity options, the SMSL D6S is the perfect choice.

The SMSL D6S is available from Shenzhen Audio