Introduction​

Let’s start with the obligatory disclaimer: Aoshida Audio provided me with this unit free of charge as a form of compensation for some shipping costs I incurred while replacing another piece of audio equipment under warranty, and also asked that I provide a review of the PS100.

This review is based on my personal views of how the unit performs as part of a headphone audiophile chain, which I honestly don’t think is the primary use case for this device. Given the cost and go-anywhere form factor, I see the PS100 being used mostly as a cheap and good-enough way to modernize legacy bits of audio equipment: think home theater receiver from just before the wireless era, or old desktop CD/cassette sound system that still works perfectly but has no way of streaming Spotify. I could even imagine this thing being velcroed to the underside of a dashboard for in-car use.

Build, Form, and Function​

The packaging for the PS100 is sparse, and that extends to the documentation, which provides basic operating instructions and a handful of specs. I had to search online to learn that this device is built around the ESS Sabre ES9023 DAC chipset, and the only way I learned what Bluetooth codec it supports is by looking through the developer option screens on my Android phone (the answer is SBC, and that’s it – no AAC, no AptX, and certainly no LDAC). I still don’t know what Bluetooth chipset is used.



The entire device is about the size of a pack of cigarettes, and the UI couldn’t be simpler: there is a single button on the front that you long-press to power on or off, and short-press to select the input source. A dim white LED indicates which source you’re using. The whole experience is rather budget-oriented, but given this device’s mission in life I’m fine with that; it honestly isn’t meant to be looked at or touched any longer than necessary. Slick, hefty knobs and satisfying clicks would be wasted here.



To keep costs down, SMSL chose to use the USB-C port for power, and didn’t even include a power adapter. This compromise creates some potential usability challenges. On the plus side, everything just worked™ when I plugged my android phone directly into the back via a C-to-C cable (more later on the sound quality of USB vs Bluetooth), however I have to assume this will place added drain on the phone battery, and if you happen to be coming into a listening session with a low phone battery and were hoping to charge your phone as you listen, you’re out of luck: you’ll have to plug your phone into the wall and stream via Bluetooth instead. Output power is sufficient but rather limited. For comparison, I set my DO200 at -5.5db output level to create an equivalent listening volume.

Weirdly, there’s an easter egg on shutdown. A very quiet male voice says something (which I haven’t yet been able to figure out) after you long-press the button to power off the device.

Features not tested​

I reviewed this unit mainly as a piece of headphone HiFi gear. As such, I didn't get around to testing the following:

• Windows drivers (for USB input)
• Optical, Coax, and HDMI ARC inputs

Test Equipment and Test Tracks​

Even before plugging in the PS100, I had a hunch the modest and inexpensive Sabre ES9023 might give the sound a harder edge, so I reached for my Beyerdynamic DT-880’s (since they are the most revealing headphones I have when it comes to treble) and fired up some tunes to get a first impression. My hunch proved to be correct: the PS100 is much sharper and more sibilant than any of my other DACs, especially when using Bluetooth input (more on this later).

To develop my impression of the audio, I went back and forth between the SMSL PS100 and my SMSL DO200mkII as the DAC source feeding into my SMSL HO200 amplifier. On the output side, I listened with both the Beyerdynamic DT-880/600 (to bring the treble forward as much as possible) and the SASH Tres 45 (which take a much more relaxed approach to upper mids and treble).

For test tracks, I gravitated toward things that would reveal sibilance and other compression artifacts in the midrange and treble, such as:

• Genesis (Duke) – Behind the Lines
• Rush (Grace Under Pressure) – Red Sector A
• David Bowie (The Rise and Fall of Ziggy Stardust and the Spiders from Mars) – Soul Love

I also threw in some tracks to test overall resolution, imaging, and presentation of the soundstage:

• Tears for Fears (Songs from the Big Chair) – I Believe
• Tears for Fears (Songs from the Big Chair) – The Working Hour
• Harry Manx (Live at the Glen Gould Studio) – Point of Purchase
• Autorickshaw (Four Higher) – Ganamurthy

Bluetooth Performance​

Bluetooth performance is by far the PS100’s biggest weakness, so let’s start with the bad news then end on a high(er) note. As mentioned earlier, I haven’t been able to figure out what chipset SMSL used for Bluetooth here, but the default – and only – codec option is SBC. That means 328 kbps with a sampling rate of 44.1khz. This, coupled with the relatively archaic ES9023 DAC chipset, creates some pretty noticeable compromises in sound quality.

For comparison, my DO200mkII connects using LDAC, and I configured LDAC in my phone (via developer options) to output at 990kbps, which should maximize audio quality. Honestly with the DO200, I am hard-pressed to tell the difference between LDAC and hard-wired USB. Feel free to take that either as a statement on the high quality of modern Bluetooth codec implementations, or a statement on the low quality of my ears as test equipment, and an inability to hear differences that other people might find obvious.

Either way, when listening to the same tracks via the PS100, the decrease in audio quality is noticeable. For starters, there is an edge to the treble that makes any sibilance in the track more prominent and annoying. Sibilance feels like it sustains longer and suffers from compression artifacting that sometimes turns a simple “sss” sound into a “sssshwuh” sound. This is all very subtle (I can think of numerous friends and family members who I bet wouldn't detect this at all) but it’s there. Upper midrange and treble also sound more grainy. Bass seems less affected but I did hear some mud and loss of precision at times in the upper bass – for example with Tom hits.

Overall, the PS100 creates an impression of less resolution and detail: in my opinion piano sounds more congested, vocals lose some of their ethereal quality, and passages that should sound “effortless” somehow don’t anymore. I also found imaging and separation to be less precise, and if an instrument or vocalist seems to be floating around me when using my DO200, it moves toward the top of my head and sounds less expansive with the PS100. There is less sense of being immersed in the music or present at the venue.

A more intimate and less revealing headphone such as the SASH Tres 45 (as compared to the Beyerdynamic DT-880) will go a long way toward softening many of the weaknesses of the PS100. This is especially true of the relatively crude treble presentation and proclivity toward sibilance. You may still hear it when you pay specific attention, but it’s less immediately distracting.

Having said all of the above, let me insert an asterisk* into the discussion at this point. When switching back and forth between the PS100 and a higher quality DAC, the differences are obvious if listening critically. But the SBC codec uses “psychoacoustic” compression, meaning it cuts information where you notice it least. Also, auditory memory is notoriously short in duration. What this all means is that after about a minute of listening with the PS100, my brain mostly forgot about the higher quality I was hearing before. It got to the point where I’d be grooving along to the music and I’d suddenly ask myself “Am I sure I’m not being too hard on this DAC? Is the sound really as flawed as I thought?” Of course a quick switch back to the DO200 would then confirm the flaws, but it’s entirely possible to enjoy a listening session with the PS100 if you turn off the critical part of your brain, especially when using less revealing headphones.

USB Performance​

Direct-wired USB reduces the treble and sibilance issues significantly, but not quite completely. Treble is presented more cleanly and without the artifacting described earlier, and midrange grain also seems to be reduced compared to Bluetooth. But this is still a less sophisticated chipset than the ES9068 found in the DO200 - the imaging is less precise, the soundstage is less immersive, and those moments of ethereal, floating beauty hit less often.

Conclusion​

It’s impossible to review the PS100 without mentioning the fact it costs less than 1/10 what the DO200 does. It is important to measure its “flaws” against the correct set of expectations. I don’t anticipate anybody here will be shopping the PS100 against a mid-fi unit, nor should they. As mentioned earlier, this is the unit you buy to bring sound someplace you didn’t have it before. It’s probably also worth recommending as a starting-point DAC to someone who’s extremely price conscious. Paired with something like the Douk Audio U3 Class A amp, you'd get a dirt cheap listening station with an upgrade path.

To me, the more interesting question with the PS100 isn’t whether it’s well-suited to its intended market – because it is – but whether SMSL should have priced it $2 or $3 higher and included a more capable Bluetooth chipset. Really, 80% of the weaknesses I heard here were due to the SBC codec. LDAC would sound soooo much better and would make the PS100 a much more compelling buy even against units costing 2 or 3 times as much. But then maybe that’s the point: SMSL has a large (some would say too large) portfolio of audio products, and a PS100 with good Bluetooth would certainly cannibalize sales from higher margin models. Regardless, it’s a good time to be alive as a headphone audiophile and used within its limitations, the PS100 is a useful audio appliance.

Introduction​

There are some amazing mass-market headphones today, but there is also an undeniable allure in the idea of finding a hidden gem. As a woodworking hobbyist and overall tinkerer, I was intrigued when I heard about SASH – a one-man operation in Ukraine making headphones (by hand) that punch far above their weight in terms of sound quality.

I went ahead and placed my order in early-June, and after roughly 7 weeks fabrication and 2 weeks shipping, I received my completed headphones 2 months later: the SASH Tres 45 ohm. Specs can be found on the (only recently launched) SASH website:

https://www.sash-audio.com/product-page/headphones-sash-tres-45-ohms

Construction and Ergonomics​

Sasha, the owner of SASH, was wonderful to deal with throughout the process and he made a point of sending photos as the build progressed. Now that I’ve seen the physical product in person, I can report that while the photos certainly look nice, these headphones have loads of character when you get to hold them in your hand. The genuine wood housings, grills, and cups in have a nice, premium appearance and feel. The yokes are chromed metal and have a purposeful look that suits the overall design. The suspension-style headband is leather under thick, high-density plastic. Everything is well-built and looks like it will last a thousand years.

Physically, these are big headphones, weighing in at ~550g. In use, I find that the headband does a good job distributing the weight, and so far I find it easy to “forget” I’m wearing them and just settle into the music. I honestly wish my Monolith M1570 did this good a job at distributing weight, but they feel like every bit of 640g every moment you’re wearing them. Clamping force with the Tres is on the tight side of moderate, though I expect them to loosen up over time like any other headphone.

The included cable (you can order your preferred length, as well as your preferred connectors) is nicely constructed and has good thickness. It’s more microphonic than I’d prefer, but it’s easy enough to get an aftermarket cable if I decide to go that way.

Performance​

Disclaimer: Sasha did a certain amount of testing and burn-in before shipping the headphones, but I have no idea how many hours. On my side, I’ve put less than a dozen hours of music through these. Are they fully burned-in? Will they improve with more time? Does burn-in even exist? Pass on all of the above … but if my impressions change down the road, I’ll try to come back here and make updates.

It’s also important to remember these are hand-made headphones, so there is almost certainly a degree of variability between different units. I have no doubt that Sasha puts a lot of care and attention into each and every headphone he ships, but that attention is going to be individual, and I suspect the result is going to be special in a slightly unique way every time.

My primary stack is the SMSL DO200 MKii DAC + SMSL HO200 amplifier, a combo that is well-regarded for clean and accurate sound, and I disabled all “sound colour” profiles in the DO200 for this review. All listening (unless noted otherwise) used the balanced 4.4mm output and cable, and the standard angled leather pads that came with the Tres.

The Test Tracks​

I have a regular reference playlist of about 25 songs that I use as “known territory” for testing and analysis. The songs below are the main (but not the only) tracks I used to write this review.

The Alan Parsons Project (Eye in the Sky) – Children of the Moon​

This track is an interesting mix of rock and orchestral elements, with snappy prog-rock riffs and percussion overlaying delicate strings. The vocals in the chorus (“children children of the moon, watch the world go by …”) rely on dynamic upper-mids and are prone to being drained of emotion and vibrancy in some headphones. And of course, there’s that inimitable “70’s sound” to the mixing and mastering we all love so much

Genesis (The Lamb Lies Down on Broadway) – Fly on a Windshield + Broadway Melody of 1974​

Another mix of rock and orchestral elements, and starting at 1:20 things get very very busy: pounding percussion, a deep and relentless bass line, crashing cymbals, a heavy layer of strings, all competing with a weakly-mixed lead guitar. It’s very easy for the presentation to get messy and things to get lost.

In the second part of the song (Broadway Melody), Peter Gabriel’s plaintive vocals are influenced by the sound signature of the headphone’s mids.

Scann-Tec (Unyt) – Unyt​

This song is all about the bass, with lots of deep-reaching synth.

Her (Her) – Five Minutes​

This song is all about the treble, and the fine line between snappy vs. overcooked

The Souljazz Orchestra (Manifesto) – State Terrorism​

The horns section in this song (everything by Souljazz Orchestra really) is just so incredibly lush and chewy. This is a perfect track to test how well a headphone can deliver those spine-shivering, toe-tapping, feel-good harmonics.

Harry Manx (Live at the Glen Gould Studio) – Point of Purchase​

This is a beautiful, intimate live recording where each individual headphone (and even individual EQ profiles) influences the perception of the soundstage and space of the studio where it was recorded. The size of concert hall you’re imagining in your head literally depends on the headphone you’re wearing. There’s also a gorgeous interplay of male vocals, female vocals, and acoustic guitar, each of which will be pushed forward or backward by any given headphone’s inherent signature.

The Holly Cole Trio (Don’t Smoke in Bed) – I Can See Clearly Now​

Holly Cole’s angelic voice tests the ability of a headphone to deliver clear, effortless mids without distraction. This is a song where I don’t want a distinctive sound signature – I just want to be transported into the ether where that voice resides.

On the flip side, I want a rich and melodic presentation of that piano. So really, I’m asking for a complete contradiction: utter transparency for the vocals, delicious harmonics for the piano.

Overall​

If I were to use a single word (well, two words) to describe the Tres 45 performance, it would be “buttoned-down”. Everything sounds neat, well-executed, and exactly where it should be. Even with busy musical passages where I’ve seen other headphones struggle, there are no sonic surprises – everything just flows.

Confident, accurate bass and lower-mids are where the Tres shines, but at the same time the relatively recessed upper-mids and treble can make the headphone sound constrained and throttled, especially at lower listening volumes. The overall detail retrieval and precision of these headphones is mindblowing considering they are handcrafted from the ground up.

*edit* As I listen to these headphones more, I am increasingly struck by their musicality. There is an organic, analog sound to these that evokes the golden age of vinyl - dim, smoke-filled rooms and obscure audiophile speaker brands playing saxophone-drenched soul, jazz, and rock fusion. Switching back and forth and A/B testing against other headphones isn't what the Tres is all about. Keep them on and sink into those seductive layers of velvet.

Bass​

The bass presentation in these headphones is incredibly clean and well-controlled. There are no resonant peaks or bleed that I can detect, nor any soft spots all the way down to around 40hz where the bass (gradually) rolls off. If I have any complaint with the bass it’s that things like kick drums, toms, and bass guitar lines in the “punch” frequencies (100-150hz) don’t hit as hard as some of my other headphones. The thump is there and it’s delivered with delicious precision, but if you’re looking for a headphone that smacks your eardrums around, the SASH Tres isn’t it – especially straight out of the box and without equalization.

Midrange​

Funny story: I’ve had my Sennheiser 660S for coming up on half a year, and in that time I’ve struggled to appreciate them for what they are. I listen to those effortless, velvety mids and I’ve always liked what I hear, but they weren’t enough to make me like the headphones. The very first thing I noticed about the SASH Tres is a very Sennheiser-like midrange, and suddenly I get it: the saxophone in State Terrorism is filled with life and passion, Harry Manx’ gravel-infused vocals in Point of Purchase are like a cozy wool blanket on a chilly night sitting around the campfire.

Those creamy mids have not only endeared me to the SASH Tres itself, they’ve woken me up to the charms of the 660S, which I found myself appreciating a lot more as I listened for the purposes of this review. That said, to my ear the mids of the Tres become softer and more veiled as you move up the frequency range. I find some female vocals can be pushed back and drained of brilliance, such as Neko Case on the song Down I5.

That sublime presentation of lower mids also lends well to certain instruments, such as the distorted blues guitar in by Vestbo Trio’s Mudslide, or Stevie Ray Vaughan’s Mary Had a Little Lamb.

Treble​

The easy-listening character of the Tres becomes even more pronounced further up the frequency range. Treble detail is there and it’s well-articulated, but it’s dialled back. This is the one aspect of the Tres where I find I most need to manage my expectations: I am fond of a bright presentation with lots of snap, air and presence, and the Tres takes a much more mellow approach to treble. Some people may find it all a little too buttoned-down.

On the other hand, for those with treble sensitivity, the Tres might be a godsend. Unsurprisingly, sibilance is incredibly well-controlled. Even on an album that I personally find to be very hot and sibilant, like Genesis Duke, the Tres has no trouble delivering all the sound with none of the ear-stabbing sizzle.

Imaging and Soundstage​

The ever-present veil in the upper mids and treble affects the soundstage exactly how you’d expect: by subduing those airy reverberations that open up the space between your ears. Instrument separation and imaging are modest. Overall I’d classify these headphones as warm and intimate, so if you’re looking for a spacious, holographic presentation, you won’t find it here – at least not without equalization.

Equalization​

I’ll talk more about the other Planar headphones in my collection – the Monolith M1570 – further down, but for now it’s worth noting that they take extremely well to equalization. A bit of EQ transforms them from being great-but-flawed to outright excellent. And here’s some more great news: same for the SASH Tres 45 ohm. All the shortcomings I’ve mentioned so far can be addressed to a remarkable degree simply by throwing a u-shaped curve onto the audio. These headphones are absolutely capable of producing lots of detail and brilliance north of 2000hz, they just don’t happen to be tuned that way out of the box.

I created a very rudimentary custom EQ using Wavelet, and while I didn’t get it perfect (things are a bit “clangy” and hot up top) I was able to move female vocals forward, create more air and sparkle, and open up the soundstage significantly.



I have not yet had a chance to apply an EQ profile with more finesse (such as something from Oratory, which I believe is now available for the Tres) but based on what I’ve heard so far, I predict the results will be excellent.

Performance with Closed Cups​

First things first: regardless of any impact on sound the closed cups that came with my SASH Tres are gorgeous, characterful works of hand-made art. Sasha offered to imprint any design of my choosing onto the backs of the cups, and I have to say I’m pleased with the outcome.

In terms of sound signature, the changes when switching to closed cups are subtle. Mids are somewhat more congested but also more impactful, overcoming some (but only some) of the thinness I discussed earlier. Upper-bass impact is also improved by the additional resonant volume. Surprisingly, soundstage and imaging don’t seem particularly impacted by the change to closed cups. If anything, there is slightly more space and air in closed configuration, perhaps due to some undamped resonance from the exposed wooden surfaces inside the cups.

Adding some EQ (the same profile that “opened up” the signature earlier) reveals more of the compromises with closed cups – for example those higher-frequency resonances off the wood become more distracting.

It would be easy to treat the closed cups as a seldom-used novelty on headphones like these, but in the case of the Tres, I feel like they suit (and enhance) the already warm, intimate signature quite well. I can see myself swapping to the closed configuration fairly often, and not just to crank some classic 2112.

Influence of Listening Chain​

I conducted all listening to this point (and also the comparison tests further down) using:

• Motorola Edge smartphone running Deezer HiFi as a music source
• Direct wired USB input to SMSL DO200 Mkii DAC, with all sound colour settings disabled
• Balanced (XLR) input to SMSL HO200 amplifier
• Balanced 4.4mm output to headphone
• Open cups and no equalization

For the purposes of assessing “scalability” and sensitivity to amplification source, I tried both the Aiyima T8 hybrid DAC/amp (single-ended output) and Fiio BTR7 mobile DAC/amp (balanced output) as sources. Both amps seem to have adequate power, so differences were subtle: the BTR7 has a slightly less spacious stage, while the T8 sounds even less spacious, but also has slightly looser bass and a softer overall presentation with less articulation, though the tube harmonics come across really nicely in the Tres.

Comparisons​

My headphone collection is quite modest, so while I’m sure there are many comparisons people would love to see, I will only offer opinions on the limited set of cans below. To make the comparison as useful as possible, I used the same SMSL stack throughout and tried to maintain a consistent level balance (despite some wildly varying impedance and sensitivity values) across all headphones.

Versus the Monolith M1570​

The M1570 is also a (big and beefy) Planar headphone, so they are an obvious point of comparison with the SASH Tres, and the comparison is mostly apt. Mostly. They are like cousins, and while the Tres went away to the city to attend finishing school, the M1570 stayed home and has been working the farm for the last 5 years. He’s bold and muscular – the kind of guy that brings you in for a hug and gives you a few solid whacks on the back to say hello.

They both have that characteristic Planar confidence in the midrange, but the M1570 does a better job extending that confidence into the upper midrange and even partway into the treble. The M1570 lends more colour to the sound signature and feels like it has more resonant peaks scattered here and there throughout the frequency range: for example on Pink Floyd’s Run Like Hell, there is some mud in the upper bass frequencies, while the Tres presents this song effortlessly.

It's worth reiterating that both the Monolith M1570 and the SASH Tres are highly amenable to equalization. With the right profile, each is sonically brilliant in its own special way.

Versus the Sennheiser HD660S​

The forward mids (and especially upper-mids) of the 660S immediately create a more spacious soundstage, but overall the mids (and especially lower-mids) are less emotional and characterful than with the Tres.

In terms of bass, the 660 feels a little over-emphasized around 120hz compared to the Tres, and also starts to roll off a good 10-20hz earlier. Listening to these two headphones back-to-back it really does emphasize how impressive the Tres sounds when it comes to bass, so long as you’re not looking for absurd movie-theatre-rumble. The natural presentation and accuracy are astonishing.

The 660S delivers treble in a businesslike and unremarkable way, but compared to the soft, veiled presentation of the (unequalized) Tres, it’s a much more complete signature. I find myself having to concentrate less when trying to pick up subtle details like cymbal hits, bells, or the uppermost registers of piano or synth.

Versus the Beyerdynamic DT-880 / 600 ohm​

The main draw (to me) of these headphones is an overall balanced presentation coupled with stellar presence, sparkle, and “snap” up top. The contrast between the SASH Tres and the Beyer 880/600 couldn’t be more stark: one of them is impeccable up to around 1500hz, the other is brilliant beyond. Even with equalization, the Tres can’t match the effortless delivery of high mids and treble from the 880.

Conclusion​

My personal tastes in headphones lean toward a less delicate, more strident and impactful presentation, so my initial listening sessions with the SASH Tres had me working hard to find their strengths and appreciate their charms.

But once you make peace with the veil in the upper mids and treble, there is a buttery smoothness to these headphones that makes it easy to listen for hours on end, even if the playlist includes hot or fatiguing tracks. These are not clinical headphones – they definitely have a character all their own – they just don’t shove it in your face. They are supremely easy to live with, and if you want to tweak the sonic character with a little EQ it’s very easy to do while still keeping the freakish accuracy intact.

Interestingly, this might be the headphone that gets me to add more classical music into my rotation: their effortless competence lends itself well to the genre, as does the softer treble presentation with less sizzle and snap.

Overall, I might not recommend the SASH Tres as a first headphone for a budding audiophile, but they absolutely deserve a spot on the shelf of someone who’s looking for a unique and quietly characterful sound signature to complement the other phones in their collection.

Just so long as you’re not a die-hard treblehead.