SMSL SU-9 Balanced MQA DAC Reviews Compendium

Compendium Updated: Oct. 21, 2020


With the release of the highly anticipated SMSL SU-9 Balanced MQA DAC and all the buzz it is generating amongst the audio community, we at Apos thought we would collect the various reviews and curate them in a compendium for you, so have an easy reference. We’ve selected snippets of the most pertinent parts of each review, but all of the sources are linked, so if you want to read the full review as it was originally written you can simply click the hyperlink. We will continue to monitor the interwebs for you and update this list as more reviews come out.


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1) Audio Science Review's of the SMSL SU-9 Balanced MQA DAC, originally published on Sept. 22, 2020:



“Wow! Another DAC nearly maxing out the distortion+noise meter in my analyzer! The SINAD of 120 dB puts the SU-9 way up there in rankings:”

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“Linearity which is a measure of accuracy is perfect:”



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Looks like we started a trend to achieve perfection in desktop DACs and the SMSL SU-9 is yet another example of that. We have another great "instrument grade" DAC on our hands providing absolute transparency to the source beyond any threshold of human hearing. If you are hearing issues I suggest you either have your hearing examined, or learn to do a proper controlled test. Either way, what you hear is what is on your recording. Guaranteed!


It is my pleasure to highly recommend the SMSL SU-9. Great job.”



2) Zeos' from Z Reviews overview of the SMSL SU-9 Balanced MQA DAC, originally published on Sept. 26, 2020:



“My point is this SU-9 is very, very good. This is probably the best sounding SMSL DAC.”

“The menu is a whole lot easier to figure out than the SU-8 menu…. The screen is 100% legible and readable — at a distance — because it's not made of blinding blue LEDs.”

“Between the SMSL M400 — the $800 DAC that they just dropped — and this SU-9...I can't audibly tell a difference. And then the SU-9 has those sound modes...I feel like that's enough. Is it an upgrade from the SU-8? Yes. Is it a 'side-grade' from the M400? Yes! I could pull that M400 off the shelf and put it right next to the SU-9, and I would have to spend endless days analyzing every particular song, with every particular headphone amp combo, to try to suss out: ‘is is this actually better?’”


3) review of the SMSL SU-9 Balanced MQA DAC, originally published on Oct. 2, 2020:



Other things that came with the SU-9 are the USB cable, a power cable, the Bluetooth antenna, and of course the manual. I would have wanted to see some batteries for the remote though, but it’s simple enough to resolve, so I’m not complaining about it too much.

Also missing are some interconnect cables, but I won’t expect it as much with a higher-end product. Since most people buying these things would have a few lying around anyway, and a good pair of RCA interconnects or XLR cables would be a must for this kind of product.


The inputs that are available on the SU-9 is quite versatile, where SMSL gave options to use USB, coaxial, and optical as standard wired inputs. Also visible at the back is the socket for the antenna, which gives the option to use Bluetooth as an input mode....The overall heft of the unit is substantial and it will sit nicely on any table. However, I would have wanted to see 4 rubber feet instead of the 3 that are on the unit, this would have made the unit less wobbly when being pressed on at the rear corners of the unit.

Menu Options

Menu Navigation on the SU-9 is quite intuitive, as I was able to navigate through the menu options when I first turned the unit on. 

PCM Filters

The options for PCM filters include your 7 standard PCM filters, which include Fast Linear, Slow Linear, Fast Minimum, Slow Minimum, Apodizing, Fast Hybrid, and Brickwall….The above filters are designed to just fine-tune the way streams are smoothed out by the DAC, but the sound color filters will allow the user to change the Timbre characteristic of the DAC. The sound color characteristics include No filter, Rich, Tube, and Crystal. These will slightly vary the sound character of the DACs sound output.

Sound Impressions

The first thing that I noticed on the SU-9 is the overall smoothness of the presentation of the sound in the entire frequency spectrum. It doesn’t sound glossed over, the overall sound character is smooth, without much of an edge, but remains impactful. I would have wanted to hear a bit of an edgier character though, maybe just a bit of a stronger bite at the end of each beat….The soundstage is presented with quite a bit of width on the SU-9, the soundstage that is formed in front is also quite respectable. The width of the stage is nicely wide as well, which then creates enough space to accurately render sound images within the sound stage.


I’ve had many MQA devices before, and I haven’t found much of a benefit to having the ability to decode MQA on a DAC….With the SU-9, I tested the MQA feature that’s available on the SU-9 by playing certain tracks on Tidal that had both a CD-quality version, as well as an MQA version. I was surprised that the difference between the MQA version and the CD-quality version was apparent.

Our Verdict

The SMSL SU-9 is a DAC with a great selection of inputs and outputs that would look great on any desktop setup. At its core, the SU-9 is a great DAC with a thick and smooth sound signature that would have at least cost double just a few years ago.

The SU-9 made me realize that now is a great time to be shopping for a DAC since one with a mature sound wouldn’t cost as much as it did a few years ago."


4) The Headphone List’s review of the SMSL SU-9 Balanced MQA DAC, originally published on Oct. 8, 2020:

Pros –

Linear sound with dead neutral tone, Coherent and layered presentation, Outstanding resolution, Intuitive UI with remote, Effective sound colour modes, High-quality BT implementation

Cons –

Only 3 rubber feet can wobble when stacked, Prominent coil whine, No single-ended outputs, Smoother top-end won’t suit all

Verdict –

The SU-9 is for those wanting a balanced DAC with a pure sound, excellent staging and strong resolving power without spending a small fortune to get it.


ESS 9038Pro –

Though the SU-9 may appear identical to the SU-8 at a glance, it’s important to note the distinction between tiers of 9038….The PRO variant is more expensive than the Q2M and draws more power in return for better performance. It is an 8-channel converter as opposed to the Q2M that only offers 2-channels, enabling it to use 4:1 summing to achieve a 6 dB SNR improvement – about double the performance in this regard since the dB scale is logarithmic.

Design –

The SU-9 also features an internal power supply that gives the device a nice heft in the hand and stability on the table in addition to omitting the need for an external power brick....Of note, the SU-9 does not have any single-ended outputs, but you’ll be able to use an adaptor cable and retain the option of going balanced down the road.

Navigation –

I am a fan of the device navigation; the integrated screen is clear and bright enough to be visible in well-lit rooms. It provides feedback for options, source and volume with the latter two being displayed constantly on the home screen. This aids an intuitive and simple user experience. 

Bluetooth –

Bluetooth is a new and welcome addition, signified by the screw-on antenna. It works without the antenna too and the antenna can be angled horizontally if below another device in a stack….With the external antenna attached, I was able to cross 3 rooms with double brick walls and the sound didn’t become intermittent.

Sound –

DACs that offer insanely good measured performance such as this often provide a very similar style of sound; that being something tonally transparent, technical and subjectively powerful. And in listening, this is indeed the case, the SU-9 is very linear, very balanced and basically tonally uncoloured. 

Tonality –

The SU-9 offers a balanced, linear and smooth sound with no notable tonal colouration. This is not a given on sources, some of which introduce colouration intentionally in order to cater towards different listener preferences. Compared to the Khadas Tone Board, a single ESS 9038Q2M implementation, the SU-9 provides a similar though notably more refined and coherent expression, especially noticeable on a micro-scale looking at individual note expression. 

Sound Colours –

[T]he sound colour modes are subtle, tasteful and effective. This makes them more useful than the overt eQ presets found on some devices that overly skew the sound and timbre. Actually, when you read SMSL’s content online, this isn’t an eQ at all, but rather, a setting that alters the level of distortion in order to tailor the sound. In turn, the effect is a little more authentic and there is a noticeable albeit subtle difference between them. 

Soundstage –

The soundstage presentation is also a highlight of this DAC, not necessarily in dimension, but mostly imaging….The SU-9 offers an excellent portrayal of distance especially. Where the lower-end DACs I’ve tested tend to push either near or far, the SU-9 organises elements into layers, each layers is well-defined and well-delineated from the next so you end up with a considerably more immersive and realistic portrayal. 

Verdict –

To say that I very much enjoyed my time with the SMSL SU-9 would be an understatement. Even from the perspective of a cynic, I did find the DAC to offer very real audible benefits over the cheaper Tone Board despite both, in theory, performing above the range of human hearing and offering excellent implementations of ESS’ flagship chip line. I was especially impressed by the SU-9’s imaging performance, offering a very layered and organized presentation with an immersive portrayal of distance and direction. It is not the most engaging source, being ever so slightly on the smoother side. But it remains a highly-resolving one with zero grain or brittleness even into the very highest registers. The build quality is good, the remote and rotary encoder navigation intuitive. The clear screen is the cherry on top, aiding straight forward daily usability. Though we are venturing into the realms of diminishing returns here, this is far from the most expensive source you can buy whilst delivering performance that sits in the same leagues. The SU-9 is for those wanting a balanced DAC with a pure sound, excellent staging and strong resolving power without spending a small fortune to get it. 

5) Soundnews' review of the SMSL SU-9 Balanced MQA DAC, originally published on its YouTube channel on Oct. 21, 2020.

Build Quality 

I have to mention that the SU-9 is among the very few SMSL units which I like its look and form factor. It does not have an odd shape, an elongated body, a tiny screen, or a weird volume knob, so SU-9 is already going into the right direction.

Preliminary Impressions

After receiving it I was a little bit underwhelmed by its size and also by its weight, a clear sign that a linear transformer can be found inside. Sincerely I don't know how SMSL did it, but it didn't lack at all in terms of slam and impact….I'm still contemplating what is actually causing this effect in the SU-9, so we are not talking about a linear or straight-as-a-line DAC, about a neutral DAC; we are talking probably about the warmest sounding SABRE DAC that I’ve tried as off late.

It has incredible textures in the base and mid-range and all my focus, all my attention was moved exactly in this region. All its naturalness on its simply awoke some very positive emotions in my body. So, SU-9 is without a doubt a warm-sounding source that is more about emotions, about body hits, about making you move while listening to music instead of analyzing your music to the smallest details.

SU-9 is a mid-range focused DAC. It is incredibly meaty, dense, and full-bodied in here, that even bright sounding speakers and headphones will start sounding much smoother and alive. Preliminary impressions are very positive and sincerely it exceeded my expectations.

Noise Floor

Since nobody tested its IEM compatibility, and since SMSL didn't publish the noise floor of this unit on its website or also on its user manual, it was simply mandatory putting it under a magnifying glass and checking if gremlins are living inside the case. For this job I used only the Benchmark HPA4 — that is simply noiseless with any IEMs at full power, it's simply the best candidate for this job. I've used the most sensitive IEMs that I have and those are FiiO FA9 and I put them in the low-impedance mode. I paused my music and I went full power on HPA4 and also on SU-9...and SU-9 managed to be completely free of any noise in this regard. It simply performed as the best DACs that I have tested, even those costing ten times the price of this unit.

I also redid my tests in a speaker setup...the Buchardt S400 loudspeakers that you see behind me are quite prone to noise coming from the source and amplifier, so this will be a very easy task. I paused my music and went full power on the SU-9, just to experience absolutely the same noiseless and clean performance. SMSL really outdid themselves with this device.

Transient Response

Transient response is by far my favorite part to talk about…. The bass notes on Rage Against the Machine “Know Your Enemy” were so obvious at first that it was almost too much bass, too much body hits, too much impact at 1:41 second mark….

SU-9 is simply a natural hitter, so it does not want to be linear and straight-as-a-line. It does not want to follow those rules, it's very mean in the base and mid-range section. It's brutal at times, it's aggressive, it's a raw-around-the-edges unsophisticated and messy. But, when it's time to land some well-placed hits and decay, does that with its chin up like it's nothing. SU-9 is not the most refined sounding digital source and not the most detailed one — it always presses the gas pedal. it's like your best friend that always looks for a fight after a drink or two, so it is brutally impactful and hard hitting and I really love it for that.

Soundstage and Sound

The stage size is not up front, it isn't collapsed at all, I'm not experiencing claustrophobia with this one, but at the same time I do feel that it is sounding by a hair less expanded and wide-open as pricier units would sound. In a headphone setup, I wouldn't be worried at all, because it didn't limit the sound stage size of my headphones and those sounded exactly as I remembered them. However, in a speaker setup, the lack of a true line amplifier inside the SU-9 and also a smaller number of capacitors were simply limiting the air that was traveling around.

If you are searching for a warmer sounding DAC, but can't afford a nicer R2R ladder DAC, I think that the SU-9 can be a really good replacement. I'm not joking because SU-9 does indeed remind me quite a lot about the good sounding R2R units with its natural and sweet sounding mid-range. It's still shocking to think that I’m experiencing all this in an ESS SABRE DAC.


Overall, SU-9 is a warm sounding source that delivers heavier bass and mid-range density at the cost of less treble presence. It isn't linear sounding and, maybe, that is for the best, as sometimes music wants to be listened to and enjoyed, not only analyzed.