Preamble:
Originally posted on my German audio review site, the "
Kopfhörer-Lounge", here comes my review of the iBasso AMP3 module, a fully balanced amplifier module for the DX200 with even a balanced Line Out.
Introduction:
iBasso Audio’s DX200 flagship audio player was introduced with the feature of having replaceable amplifier modules.
Some months after the player was released, the first amplifier module, “
AMP2”, was introduced. It featured a fully single-ended internal structure with a technical “active balanced ground”/”virtual ground” implementation and a slightly smoother presentation compared to the bundled “AMP1” module when doing volume-matched, comparative listening.
Now after some more time has passed, there is another new amplifier module available. It is logically called “AMP3” and features
only balanced outputs.
What makes it special (at least I haven’t seen this on any other portable audio player) is that its Line Out is also a balanced 2.5 mm TRRS output wherefore the DX200 has become even more interesting as a pre-amplifier for people with compatible speaker gear who want to take advantage of this feature.
How and if the AMP3 differs sonically from the AMP1 module’s balanced output is one thing among others that I find out and summarise in this very review.
Full disclosure:
I was provided with a free sample of the AMP3 module for the
iBasso DX200 that I reviewed some time ago. I also
measured and reviewed the AMP2 module as a follow-up.
The AMP3 module was sent to me for giving my honest opinion on it as well as writing an (as usually) unbiased, honest and unpaid review. Before I go on, I would like to take a moment to personally thank iBasso and especially their Paul for the continued generosity and trust.
Technical Specifications:
http://ibasso.com/cp_xq_dy.php?id=5696
MSRP: $199
2.5 mm Balanced Headphone Output:
Max. Output: 6 V (RMS)
Frequency Response: 10 Hz – 45 kHz (-0.5 dB)
SNR: 124 dB
THD+N: 0.00025%, -112 dB (32 Ohms @ 2.4 V (RMS))
DNR: 124 dB
Crosstalk: -132 dB
2.5 mm Balanced Line Out:
Max. Output: 6 V (RMS)
Frequency Response: 10 Hz – 45 kHz (-0.5 dB)
SNR: 124 dB
THD+N: 0.00022%, -113 dB
Crosstalk: -114 dB
Unboxing & Delivery Content:
The amplifier module arrives in a black cardboard box with a white sleeve around it, reading “iBasso Audio AMP3”. On the back, one can find the amplifier module’s serial number.
Inside, of course except for the module itself, one can find a warranty card as well as instructions on how to change the amplifier modules. A small screwdriver to change the modules comes included, too.
Therefore one will find everything that is needed to change the modules in this black cardboard box that can also be handy for storing the amplifier module that is currently not in use.
One additional accessory in the box would come in handy though: a small dust plug to protect the output that is currently not in use and to avoid using the wrong output by mistake.
Visual Appearance & Build Quality:
The AMP3 module looks basically just like the AMP1 and AMP2 module, except for having two 2.5 mm TRRS outputs and the lack of the large “Reference DAP” inscription the AMP1 has. Other than that, the text on the back is the same.
Since it is also made of black as well as silver metal, it feels very solid and is built well.
On the lower right hand side, one can find an inscription saying “AMP3”.
Changing the modules:
… is a super simple process.
The two screws on the side of the amplifier module that is attached to the DX200 have to be loosened using a screwdriver, for example the one that comes with the module itself. Removing the screws entirely is not required but two or three rotations are already enough to loosen them.
Then, the module can be slid down and lifted off.
After that has been done, the other module can be put on, slid in place and then the screws can be tightened (be careful not to overtighten them though).
Using the Balanced Line Output:
Feature- and spec-wise, the
DX200 is undeniably a formidable and premium portable high-end digital audio player. Therefore it does absolutely make sense to also use it in a proper speaker setup.
Given the AMP3 has now got a fully balanced Line Output as well, this also means that the
DX200 can now be used as a fully balanced pre-amplifier with mono-block power amplifiers.
For stereo amplifiers however, please make sure that they have separated grounds on the inside, else you would short the circuit, which you don’t want to do!
Anyway, while a balanced signal transmission only mainly makes sense if the cable is very long, it can also bring a slightly better measured performance that, while probably not audible in a blind test, does give a better feeling nonetheless.
- - -
Over the past 10 years, I have pretty much reduced (/downgraded) and abandoned most of my stereo speaker audio gear for my main
Swans M1 (that I would likely replace with a larger set of active Neumann/Klein & Hummel monitors if speaker audio were still as important to me) and DIY Cyburgs Needle computer speakers.
Long gone are the large, once expensive Pioneer and Sony amplifiers, in favour of small and rather inexpensive digital Pro-Ject mono power amps and a DIY pre-amplifier with a digitally controlled analogue volume control circuit.
So really nothing fancy or high-end and mostly laying in abandonment, but if I wanted to, I could re-activate my setup anytime.
So after soldering a matching cable for my Pro-Ject mono-block power amps (that logically have separated grounds wherefore they can be used with the AMP3’s balanced Line Out), I was ready to use the
DX200 as a pre-amplifier for my Pro-Ject mono-block power-amp- + Swans M1-setup.
As the Line Out is variable, the
DX200 can be perfectly used as a pre-amplifier for this setup. And not much surprisingly, it does work perfectly for this application. Be careful though, since it can maximally output 6 V RMS through the Line Out, too, according to its specifications.
Is there a noticeable improvement over using a single-ended Line Output? Not with this setup at least, but my Swans speakers are not particularly high-end either and, while their separation is very good in their price class, they are beat by numerous smaller active studio monitors when it comes to control and resolution even though they cost the same as my Swans or even less. But I wouldn’t really expect a larger difference even with a high-end stereo speaker rig as long as the previous line output was not too shabby.
What is also possible though is using the AMP3’s balanced Line Out with a portable headphone amplifier that has got a balanced Line In, however there are just a handful of them and I don’t have any of those on hand.
So let’s move on to the next section.
Sound:
Before heading over to a the more detailed description, it is
very important to note that it is required to have at least firmware version FW2.5141 installed on the
DX200 in order to have full compatibility with the fully balanced AMP3 module.
Specs compared to AMP1:
Frequency Response, Output Impedance:
One of the most basic and fundamental things an audio player should have is a flat unloaded frequency response in the important range of 20 to 20000 Hz. While it is anything but sorcery to achieve this in modern days, some (however mainly inexpensive and rather no-name) audio players still fail to do that.
But even when having a flat frequency response without any load at all or with a simple load (such as a headphone that has got the same impedance over its entire frequency response), things are getting much more difficult with most multi-driver in-ears that have got more than just one driver and a crossover circuit that causes the in-ears’ resistance to vary along with their frequency response.
If the audio player’s headphone output doesn’t have a low output impedance, the in-ears’ frequency response and therefore heard tonality will be skewed and they will (depending on the player’s output impedance and the in-ears’ specific impedance response) sound more or less different than when driven by an audio player that has got a low output impedance.
To maintain an unaltered sound even with low impedance multi-driver in-ears, it is therefore best to have an audio player that has got an output impedance of less than 1 Ohm.
- - -
Using my regular RMAA methods to capture the unloaded and unloaded frequency response won’t work with the AMP3 module since neither of my soundcards/audio interfaces have got any balanced inputs.
So no loaded and unloaded RMAA frequency response measurements this time.
However, given their past amplifier modules, amplifiers and digital audio players, it is
highly unlikely that iBasso would implement anything other than an absolutely flat frequency response in the AMP3 module.
Upon request, iBasso Audio informed me that the AMP3 has also got a nicely low output impedance over its balanced headphone output (around 0.36 Ohms), which would be a pretty ideal value for about any output-impedance-critical, low impedance multi-BA in-ear, and based on iBasso’s honest disclosure of specifications in the past, there is little to no reason to not trust them.
- - -
And while I am not able to do electric RMAA measurements of the AMP3 module, I was able to perform acoustic measurements using my
Vibro Labs Veritas setup and the
Fidue SIRIUS as connected in-ear, tightly sealed in the
Veritas coupler using that blue modelling clay stuff that came with it. However, instead of using
my usual Veritas setup soundcard, the
LH Labs Geek Out IEM 100, I used the DX200 in USB DAC mode.
What I did was to measure the output from AMP3’s headphone output and compare it to what AMP1 outputs over its balanced headphone output.
Subtracting one signal from the other, this is the result I got:
A flat line that indicates that both modules output the exact same frequency response.
I then also measured AMP1’s 3.5 mm headphone output and compared its signal to what its balanced 2.5 mm output puts out, and the result was the same. Given that I already RMAA-measured AMP1’s single-ended headphone output’s frequency response with and without load, this logically leads to the conclusion that both AMP1’s and AMP3’s balanced outputs are just as linear and neutral when it comes to frequency response.
Hiss:
I consider myself as someone who is rather sensitive to hearing hiss and have also got some very sensitive in-ears (none of them is terminated with a balanced connector though since I am an “everything stock” person and do personally/privately not really need a balanced connection).
So with the right in-ear, I can hear hiss to a varying degree with almost any digital audio player.
Using the AMP3’s headphone output with the
Fidue SIRIUS,
iBasso IT03 (
iBasso CB13 cable) and
DUNU DK-3001, there is only a very slight amount of hiss noticeable with empty audio files or during silent passages. It’s lower compared to my
Chord Mojo’s headphone output, however not as quiet as from AMP1’s or
AMP2’s single-ended headphone output. Given the higher voltage though, this is no surprise, and considering that driving power, the amount of audible hiss is comparatively very little.
What’s interesting is a comparison between AMP1’s and AMP3’s balanced headphone outputs. Directly comparing the two outputs, AMP3 has only got
ever so slightly more hiss than AMP1 in quiet passages (the difference is extremely small and only noticeable when comparing both head-to-head in within less than 10 seconds).
So yeah, the amount of hiss is still nicely low (although the output is not entirely quiet with sensitive in-ears, which would however also not be realistic with that voltage output) and hasn’t really changed compared to the AMP1 module.
Subjective Perception of Transparency, Precision & Soundstage:
Now to the rather subjective part of my review. My opinion and experience regarding the perceived “character” and “transparency” of source devices and amplifiers is this one: there can be an existing audible difference between various devices, but it should definitely not be overrated – simply because the basic character of a headphone won’t be completely changed (if the circuit follows a clean design philosophy and the output is load-stable), but sometimes rather slightly “shaped” and is usually very subtle in many cases, and is (in most cases) just slightly present (if even) and not “huge” or like “totally different classes” or “night and day”.
I am not a fan of exaggerations and hyperboles here because as long as the objectifyable parameters of an audio player are neutral and not too shabby (loaded frequency response, distortion, crosstalk, dynamic range, noise, …), the audible difference, if there is any, will be quite small at best if two devices are compared with proper volume matching that cannot be done by ear but only with instruments, since even small differences in loudness can be perceived as a technical advantage by our ear and brain.
A more detailed, German article written by me concerning the “audible difference between comparable audio devices, if there is any” can be found here:
http://kopfhoerer-lounge.blogspot.de/2016/04/Eigenklang.html
So let’s go on with my subjective impressions and observations of the AMP3 module’s balanced headphone output (for this critical listening, I mainly used the
Fidue SIRIUS,
iBasso IT03 with the
CB13 cable and my
Audeze LCD-X):
The description on their website states that iBasso is using a patented balanced design for the AMP3 module that lowers the odd harmonic distortion while it keeps the even harmonic distortion, which results in a comparatively “full and musical” sound.
In this paragraph, I could actually copy and paste most of the things I wrote about AMP1’s balanced output in my
original DX200 review and only change a few lines (the bass appears ever so slightly more impactful due to a slightly softer response, vocals appear slightly more “organic” and there is a slight change in cymbal attack – however as both amplifiers output a flat frequency response and the differences lay in the harmonic distortions, the audible differences are clearly more like nuances, which was to be expected. This also reminds me of the
Elekit TU-HP02 headphone amplifier that has got a “trioderized” circuit that adds harmonic distortions to the sound, and listening to that amplifier for my
review, I was also rather surprised that the added smoothness and organic-ness were quite small compared to a an amplifier that doesn’t have that added distortion and circuit).
So no, there is no huge difference between the two outputs – in fact, the difference is only rather expressed in nuances.
There is some more organic-ness going on compared to AMP1’s balanced output, however the “character” is not as smooth and analogue-ish as
AMP2’s headphone output or the
Chord Mojo. Comparing AMP3’s character/timbre to
AMP2, it even sounds a bit analytical.
So instead of describing everything twice, I decided to move that description and the comparison over to the next paragraph.
- - - - - - - - -
Compared with the AMP1 module (balanced output):
In my
original review of the DX200 that of course featured the bundled AMP1 module, I found that its balanced headphone output had more of an “aggressive”, slightly brighter timbre and appeared even more spacious during volume-matched comparisons with its single-ended headphone output.
- - -
So as I mentioned, the difference I was hearing between the two amplifier modules was certainly smaller than I initially thought, just as back in 2015 when I reviewed the portable
Elekit TU-HP02 headphone amplifier with a “trioderized” circuit.
Interesting to notice is also that the difference between the two modules, at least for me, is easier to spot when switching from AMP3 to AMP1, while it is certainly more difficult (I would even say almost impossible under objective circumstances) when doing it the other way around (switching from AMP1 to AMP3).
Anyway, what I am hearing is a slightly more “organic” appearing “character” coming from AMP3 compared to AMP1. Also, attack of higher frequencies appears a tad less “aggressive”. The presentation of the midrange and highs is therefore what I would call slightly “defused” while not losing any detail or information, which wouldn’t be really possible anyway since the difference is in fact relatively small. For instance, the difference in terms of sound “character” between the
DX200 and
Cowon Plenue 2 or
Chord Electronics Mojo is a good bit larger and more noticeable in comparison.
Comparing the two, switching from AMP3 to AMP1, AMP1 appears to have the slightly “sharper” cymbal attack. The two amplifiers don’t really differ in terms of perceived brightness or smoothness, it’s just that the presentation is a little more organic using AMP3.
The comparatively biggest difference apart from that slight bit of extra organic-ness, if it can even be called “big” since it’s just rather a nuance and since both amplifiers have got a flat frequency response, is happening in the lows that appear a little more “impactful” with AMP3, which I would say is because they tend to be a little softer compared to AMP1. Not any less detailed or any less controlled, just slightly softer.
When it comes to transparency, there isn’t really a difference – both modules are on an identically high level.
Moving over to the spatial presentation, AMP3 seems to have barely more width and barely less depth compared to AMP1 – but those are even smaller differences than the ones in the other areas, so I would call the soundstage basically identically spacious, large and three-dimensional.
So what’s the gist?
AMP3 adds a little more organic-ness to its character compared to AMP1’s balanced headphone output, while the presentation is still clear and clean, just with a slightly “defused” midrange and treble attack – basically what some people would call a slightly more “analogue” sound. So AMP1 is slightly crisper while AMP3 has got the slightly more organic presentation through its balanced headphone output using sensitive in-ears.
Keep in mind that those aren’t large differences but rather small nuances when regarded from a more objective point of view.
Conclusion:
iBasso Audio’s AMP3 is the right choice of module for everybody who feels to be in need of a balanced 2.5 mm TRRS headphone output but wants a little more “organic-ness” and perceived impact compared to AMP1’s balanced headphone output, while achieving that by using amplifier modules instead of carrying a separate amplifier or using the EQ the player provides.
It is also the module dedicated to those who want to have a fully balanced Line Output.