Compendium Updated: Dec. 13, 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:”
“Linearity which is a measure of accuracy is perfect:”
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.”
“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?’”
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 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.
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.
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.
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."
Linear sound with dead neutral tone, Coherent and layered presentation, Outstanding resolution, Intuitive UI with remote, Effective sound colour modes, High-quality BT implementation
Only 3 rubber feet can wobble when stacked, Prominent coil whine, No single-ended outputs, Smoother top-end won’t suit all
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.
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.
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 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.
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.
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.
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.
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.
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.
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 flow...it 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.
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 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, everything-in-an-instant...it 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.
SU-9 DAC that I will be testing today is also one of the most affordable DACs capable of fully-unfolding and natively decoding MQA files, it has the best Bluetooth receiver on the market, the highest performance commercial DAC chip, an easy to use interface via its LCD screen and everything is wrapped with a $439 price tag.
Design & Build Quality
I have to mention that SU-9 is among the very few SMSL units which I like its look and form factor.
There are 3 rubber feet underneath the unit and if you have heavier power cords as I do, it might lean to the right. You can separately buy few additional rubber feet, detach the one in the middle and put two in the corners so it will not wobble on your table. I find the build quality really nice and I have close to zero complaints.
Under the unit, I am spotting an unknown 7-pin connector, I presume that SMSL will soon unveil a device, maybe a full-fledged streamer that can be docked to SU-9. SMSL didn’t mention it anywhere, pretty curious about this one.
All the features of SU-9 can be controlled via its remote control or via the volume knob that doubles as a joystick for its menu.
Tech Inside SU-9
SMSL are quite proud about this one as they included one of the best chipsets you can find right now on the market. At its core, stays an 8-channel ESS 9038 PRO DAC chip that will be providing a true balanced output. 9038 PRO is making the best team with their own voltage regulators, so ES9311 was used in here.
I’ve spotted 4 crystal clocks – that is a higher number than usual, most probably 3 of them are used for PCM material and one for DSD material.
What is a bit unusual was seeing the XMOS XU-208 (1000 Mips) instead of the XU-216 (2000 Mips) that is recommended for MQA playback.
SMSL also included the newest and the highest performance Bluetooth receiver that is supporting all Bluetooth codecs available as SBC, AAC, AptX, AptX-HD, AptX-LL, LDAC and UAT for up to 1.2 mb/s data transfer and up to 192 kHz sampling frequency.
There is a decent number of metal-capacitors for power storing, their size is not that impressive so I’m not that sure if I will be experiencing a really nice punch into the chest in a speaker setup, will see about that soon.
All in all, there are small compromises that needed to be made to achieve such a low price point, but its digital and analog sections are looking very good, so I’m expecting some nice sonics out of it.
I. Preliminary Impressions / Timbre
I couldn’t believe my ears how much raw and mean energy was emanating from this small thingy that was looking more like a midget next to bigger digital sources near it.
Benchmark HPA4 is liking a hotter signal than the industry standard 4V via XLR, Element X is outputting 4.5V and that makes HPA4 slightly bolder and harder slamming. SMSL thingy is outputting a stronger 4.7V via XLR if I am disabling its preamp and the next minute, I was having goose bumps all over my body. It punched way above its price point and weight class.
The amount of bass and midrange presence was through the roof in this one and I am still contemplating what is causing this.
We are not talking about a linear and straight as a line DAC, not at all. We are talking about probably the warmest sounding ESS-Sabre based DAC I’ve heard of late.
I’m most impressed by midrange density and if a DAC manages to render that correctly, there is a huge chance of having an amazing tonal balance. SU-9 is a midrange focused DAC, it is incredibly meaty, dense and full-bodied in here….SU-9 is not sounding like a device that cost less than half a grand, oh boy, it is far from that and can be easily compared with much nicer digital to analog converters.
II. Noise Floor
SMSL really outdid themselves with this device, as besides being a very natural performer and an impressive eardrum kicker, it is also dead silent with my headphones and speakers. I redid my tests with its optical and coaxial input in the living room and to my surprise both seem as clean and free or any jitter, which is pretty amazing as lots of people are using their DACs with a Chromecast Audio, a gaming console or digital receiver and SU-9 should work flawless with any of them.
III. Transient Response
This is by far my most favorite chapter to write about…. Normally I would use a song like Istanbul 1:26 AM to test the soundstaging capabilities of a loudspeaker or headphone, but the amount of slam coming out of this thing makes even a song like this very engaging and alive. There are many things happenings in this song, yet I locked my hearing on those snare drum hits and tambourines. I could never imagine that that I will be enjoying oriental music that much, those instant attacks and decay of these notes were so mesmerizing that I couldn’t look away. I was surprised that every note was defined and really outlined, tambourines sounded extremely snappy and engaging. It never crossed my mind that I would be tapping my feet on a relaxed song. In the middle of the song, there are some afro-cuban bongo drums on my left, a saxophone in the middle and a tambourine on my right, all sounded so defined and so far away from each other, there is simply too much air between them, yet none of those instruments are losing energy and tempo.
IV. Resolution & Transparency
SU-9 is a detailed sounding DAC and it will show small details and nuances in your music.
SU-9 presented itself brutally honest, everything felt extremely detailed sounding, even the slight beeping sound in the right channel was not hiding at all.
Overall, SU-9 offered a higher transparency compared to midrange DACs and a mind-blowing detail retrieval that I was not expecting at this price point.
V. Soundstage & Depth
As a general rule of thumb from the flock of D/S DACs, the ones based on ESS-Sabre chipsets will sound more up-front, cozier and smaller compared to the rest. R2R DACs and FPGA DACs are pretty much the absolute rulers when it comes to things like stage size and imaging.
In the living room, it was clear that the lack of a true line-amplifier (preamplifier) in SU-9 and probably the smaller number of capacitors didn’t push the sound that far from me. Please understand that I am exaggerating a bit, I am still enveloped by music and sounds are coming from different angles, but the void space between each note is smaller and there is less air in the room.
However, do note that wide sounding albums like live concerts, orchestral work, soprano voices and others were not botched at all, only by a hair those sounded more intimate, closer to me, some voices felts like whispering directly into my ears, spooky at times but enjoyable nonetheless.
I want to be clear that SU-9 will still increase and decrease the stage size depending on the recording and gear used and if a record is meant to sound big and airy, it will sound that way with a small decrease of its size compared to top of the line DACs. Some bigger capacitors and a nicer power filtering would not limit the soundstage size and if that is crucial to you, look no further to the SMSL M400 DAC.
VI. Frequency Response
SU-9 feels ballsy, mean and rebel in the bass region, it is extremely good in here, I almost want to call it a bass heavy source, but that is not the case. It simply increases the perception of slam and impact in this region, something that is incredibly pleasing with some particular music….Not going to lie that I really enjoyed the hell out of it with meaner sounding music, it simply called my name and SU-9 delivered all the raw energy of said music.
Mid-bass is exactly the same, slightly elevated and louder sounding, always asking for the attention of the listener.
The midrange was also improved tremendously, the voices felt heavier, guitar players swapped their amplifiers with nicer ones, violins were weeping with more emotion and voices would never pass unnoticed. Everything in the mid-section felt more defined, meatier and heavier sounding.
Treble is having a very good extension, presence and detail. It is the only range that is not overdone or elevated, yet there is plenty of driver movement in here. Texture is nice, drum impact is top-notch, snares are scary real, cymbals are metallic and raw sounding. The only thing that is missing in action is brightness and teeth clenching shrillness. SU-9 will render your treble nicely, but it will not induce unnatural excessive ringing in here. It might sound like rolled-off at first, but the more you listen, you start realizing that is not the case.
Overall, SU-9 is a warm sounding source, that delivers heavier bass and midrange 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 and enjoyed, not only analyzed.
VII. MQA Experience
SU-9 is coming with a full blown MQA decoder that will fully unfold an MQA file before natively playing it.
I’ve tried several MQA albums, it locks on the signal quite fast and the MQA logo will appear on its screen.
As you can expect, it worked very well with MQA files, once it locked on its stream I will playback all those files without issues. In case you want to listen to an MQA file from an exact spot, say from the second minute, it will need on average about 1 to 3 seconds before locking in again. It will lock faster with 44.1 kHz files, and slower with 192 or 384 kHz files. I redid my tests with Matrix Element X that uses a faster XU-216 chipset and it locks on average twice as fast compared to SU-9. I was a bit skeptic that XMOS XU-208 inside the SU-9 would work flawlessly with MQA files, but all my fears are now dust in the air. SU-9 is a bit slower in locking on the MQA stream, but everything else works exactly as it does on Element X.
If you are streaming a lot of music as I do, SMSL SU-9 is still one of the most affordable MQA capable DACs that also happens to sound very good.
The interesting part was designing an ESS-Sabre DAC from the scratch that doesn’t sound as one, at all. if I wouldn’t check its spec sheet, I would never guess I’m listening to one and this part alone proves again that the DAC chip is only a very small portion out of a much bigger story. SMSL was able to transform a linear and über-transparent chipset into a sweet, smooth and natural sounding digital creature. Its noiseless performance was impressive with sensitive IEMs and its lightning quick transient response will impress a speed and slam addict as myself. Its MQA performance was flawless and the same can be said about its Bluetooth performance with a rock-steady signal even with 3 concrete walls between it and a smartphone.
I am extremely happy that I am experiencing such a complete package (DAC, Preamp, full MQA decoder and a Bluetooth receiver) at such an affordable price point. I really don’t want to throw awards left and right, simply because only the best units deserve one, but considering how much fun I’ve with a DAC that costs only $439 and its immaculate performance, I can’t go without awarding it our highest Golden Award! SU-9 exceeded my expectations and it simply deserves one. Congratulations to the team and l look forward in testing their next digital creatures!
The SU-9 is the updated version of the SU-8 which was quite famous too and has gathered fair amount of positive reviews….The SU-9 comes with ES9038PRO DAC which is currently the top performing DAC from ESS, it comes with a lot more features and upgrades from its predecessor. Few notable upgrades are the screen which made the navigation way easier (which I will discuss later), it supports MQA now as well and I will show it later as well as it works well with Tidal Master. Lastly it supports Bluetooth playback which is bluetooth 5.0 and it also supports LDAC and even the latest bluetooth audio technology, the UAT (Ultra Audio Transmission) which allows 192 kHz sampling rate and up to 1.2 Mbps bit rate which is a good news. The SU-9 is priced at 22,000 Php (439.99USD) which is almost twice the price of its predecessor, but given the upgrades I’m confident that it is definitely worth it.
The S.M.S.L SU-9 comes with CNC milled full aluminum casing….Looking at the its back, it is overloaded with numerous ports , there’s bluetooth antenna, balanced output (XLR), power cable input, optical input, coaxial input, remote window, RCA output, and USB input. I used it for a while now and ports feels rigid and same thing goes to knob. As far as the packaging goes, there’s nothing special about it, honestly it is just decent considering the price, what’s inside are the SU-9, remote control, power cable and Bluetooth 5.0 antenna.
Despite using a very simple UI, it is user friendly and easy to grasp without even reading their manuals (cause I didn’t tried to read it all). Home screen tells the connection type, file format and the volume. Using the remote or the volume knob (which is a bit harder to use) you can navigate through other options.
This time, I tried to be as meticulous as possible, I tried “GOAT” by Polyphia as soon as I decided to write this review, and man it’s speed complemented my HIFIMAN SUNDARA which is known for its fast bass. Sub bass is truly present here and it is being rendered with excellent transparency and texture, there’s nothing I can complain with this DAC, of course my experience is truly limited with DAC/AMP that I’ve already tried such as the iFi Micro and relatively few dekstop DAC such as the Burson Swing which is much pricier than the SU-9. I can easily rate this guy above every sources that I’ve tried so far. The bass of SU-9 is not too clinical since there’s decent thickness, despite that it is still amazingly detailed and transparent with nice depth and speed too, definitely an impressive bass tuning.
For the lower mid-range I actually used “Sanctuary” by Joji and it is truly a linear DAC, I usually listen with this track with mid-forward sources since I really like Joji’s vocals but with this DAC it is placed in the middle ground with zero hint of emphasis. I can’t hear any coloration on it’s presentation which means that the timbre of mid-range sounded really natural with a perfect balance between lushness and transparency. Upper mid-range...never sounded shrill nor sibilant yet it isn’t recessed too, it is perfectly positioned with accurate timbre, nuances from Reese Lansangan’s “For the Fickle” is audible, it is textured rather than detailed but it is not presented in a thin manner which is quite rare. In an audiophile’s perspective, the SU-9’s mid-range is commendable, but for me who loves intimate vocal presentation this is just okay, nonetheless the technical aspect of its mid-range is just note-worthy.
Despite being reference-ish, the treble of SU-9 is far from being harsh at least based on the tracks and gears that I’ve used along with it. Playing “Asphyxia” by Co Shu Nie, I find the treble to possess just the right amount of sparkle, it is quick and resolving. I would say that they achieved a nice tuning here, it is quite relaxed due to its airiness but at the same time it is detailed too, I can’t really find any major flaw here, my minor gripe would be that it slightly lacks energy due to its uncolored presentation nonetheless with everything it offers such as resolution, speed, airiness and extension I wouldn’t mind if it sound a bit unenergetic.
Sound Stage and Resolution
The SU-9 excels with both, it is holographic and truly resolving at the same time. I wouldn’t say that it is too clinical or analytical since there is some hint of warmth but it can still pass as flat. Vertical and horizontal magnitude of the sound stage feels awesome, headroom is very sufficient too as I said it feels holographic and it really matches well with open back Headphone along with decent amplifier. Imaging and layering are superb too, it is accurate as I can pin point the positioning of instruments especially in live recordings. I just want to include the noise floor of this DAC, it is really clean and dead silent and this is maybe due to its ridiculously low THD+N. Going to its resolution, as I’ve said several times in this review, the SU-9 delivers sufficient details without sounding boring, from lows to highs, everything is rendered with commendable resolution (especially in the midrange), it is clean and quite transparent too!
Sound Signature and Comparison
The S.M.S.L SU-9 is undoubtedly reference level DAC, with near flat sound signature (slight warmth) and excellent detail retrieval quality.
The Hifiman Sundara has been with me for more than a year and honestly, not even one IEM manage to equal the speed and transparency of the Sundara which made it my standard. This pairing has technical prowess but it may sound a bit too thin for some. Bass is deep enough with commendable resolution and speed, mid bass is really tight with great accuracy but it lacks weight and warmth at least for me. Midrange sounded clean and transparent with natural timbre, lower midrange is quite flat and has decent body (I wish it is a bit warmer), upper midrange came out sweet and quite intimate especially the female vocals. Treble has good sparkle, extension and speed though it slightly lacks air, it is extremely resolving and that is due to the excellent technicalities possessed by the SU-9. Sound stage is pretty holographic, very good openness which leads to remarkable imaging and layering.
The Starfield is innately warm and has natural vocal timbre with slightly sluggish bass response. Pairing it with the lovely SU-9, the mid bass became slightly quicker without losing the nice sub bass extension and rumble, the lovable weight of its bass was retained, resolution is noticeably better compared with other sources but it still leans toward smoothness. Lower midrange is as natural as ever, male vocals came out really well with good amount of lushness and more than enough amount of details. Upper midrange doesn’t sound that peaky, it is quite forward though and is considerably intimate without sounding thin. Treble didn’t improved that much from other sources, it is still the least dominant among the three but there’s some imorovement in terms of speed and sparkle, it is more detailed too. Sound stage is still IEM level in terms of magnitude but both imaging and layering are simply an uograde from my portable sources.
As I’ve said with my Freya review, I really can’t recommend this IEM for someone who’s thirsty for details and critically listen with their gears on a daily basis, but somehow the SU-9 pushes the Freya to its limits by giving it better resolution and more 3d-ish sound stage. Sub bass still has a moderate extension with better texture, mid bass is slightly cleaner with nice weight and good attack and decay speed, it is still smooth but there’s an improvement with regards to textures and details. Midrange sounds really pleasant, nice balance of warmth ans clarity, the synergy of the two benefitted the overall timbre of the midrange as lower and upper midrange both sounded natural, it never sounded shrill nor peaky. Treble still sounded smooth and quite relaxes, it sounds slightly morr refined and there’s a slight added sparkle up top but the overall signature didn’t changed that much.
I tried several DAC+AMPs such as the iFi micro iDSD, iFi Nano Black Label, Chord Hugo I, iFi Hip Dac and even some desktop DAC like the Aune X8, and honestly the SU-9 is comparable to the Micros and Hugos in terms of sound quality alone…. (based on IEMs only since Headphones are far more dependent with amplifier). It is quite expensive at 25,000 Php (450 USD) but I swear, the usability, features and sound quality easily justified its price. Top of the line sound with highly remarkable resolution and sound stage (accuracy and magnitude), definitely hands down.
The SU-9 comes in at $440. It is using the ESS ES9038 DAC chip, and as far as other things worthwhile to mention, it is a fully balanced stack, so XLR and RCA out. It supports PCM up to 768; DSD I believe up to 512. All the bluetooth formats that you would want, UAT/LDAC/APTX/HD etc. As far as inputs, you have USB optical, coaxial, and bluetooth, so pretty much all the inputs that you would want except for possibly AES, but nobody really uses AES outside of the pro scene.
SU-9 also has full MQA decoding. The SU-9 is an ESS-based stack and I personally am not a fan of ESS-based DAC, I tend to prefer AKM because I do typically hear the famous “SABRE glare,” as is known to be be called, where a lot of ESS-based DACs sound a little bit bright and kind of harsh. I've had this problem with a lot of ESS-based stuff, be it dongles or other lower end DACs, like the TOPPING D10 I think is a really good example of what SABRE glare sounds like in a DAC. With the SU-9 I really don't have any issues with it in terms of SABRE glare; there really wasn't anything bright or thin sounding about it to me.
Now moving into the features of the SU-9, it also comes with the SMSL remote, so you do have full remote control. On the remote you can change the volume, you can mute, you can switch your inputs and I think one just goes right to your bluetooth.
Moving into the menus, first up you have “input” so you can switch between USB, optical, coaxial, and Bluetooth PCM filter. You can pick your filter as “fast linear,” “slow linear,” “fast minimum,” “slow minimum,” “apodizing,” “fast hybrid,” “brick wall” … so you have a lot of filters. Not going to get into them for the sake of time.
For DSD filters, you have all these options (e.g., 47k cuttoff, 50k cutoff etc.), which I don't use, I don't really care for DSD.
For sound color, now these basically add distortion to simulate things like “tubes” or “crystal”, which makes them a little bit brighter. “Rich” adds a little richness to the sound, so you can play with these if you want. They don't work as well as an actual tube amp or anything like that, but they can be kind of interesting to play with, but I tend to be a little bit more of a purist at least when it comes to DACs. If I'm going to EQ something I’ll just do it with either a software EQ or actually get a tube amp, but you can play around with those which are cool.
Then we have a pre-mode setting, which is a “volume variable” or “volume fixed.” This just basically either enables or disables the volume knob, so if you are always going to be using this with a headphone amplifier then you can just leave it on “fixed,” because you're never going to need to change your DAC volume, but if you maybe use it with speakers or something like that then you can leave it on “volume variable.”
There’s a setting called “DPLL,” which basically just controls USB jitter, a very niche setting that not many people are gonna need. “Reset” resets everything to factory and “version” displays your software version.
Now in terms of sound for the SU-9, it really surprised me for how good it sounds. As I mentioned it does lack a lot of the SABRE glare that I so often have issues with in ESS-based DACs. The SU-9 also has surprisingly good staging and imaging, much wider than the M200 was and it actually stages surprisingly well.
The other thing that really struck me about it was the detail. It is a very detailed DAC and that seems to sometimes be a quality that a lot of people associate with some ESS-based DACs, which I usually think tends to be more because of the brightness, but other people could say it's because they don't have the “AKM velvet,” which a lot of people say smooths over some areas of the sound. Generalizing DAC chips like this is not generally the best idea, because it doesn't particularly matter that much. It's more that you know the filters and everything else around the DAC that makes more of a difference than the chip itself.
The SU-9 is really detailed for its price point with really good staging, surprisingly dynamic, very good at resolving little micro details, and for its price it is a solid contender. It is one of the better DACs I have heard in the price range, which is very surprising because I have historically not been much of a fan of SMSL DACs, but the SU-9 really stands out as being a very solid DAC offering. For its price point, its feature set, and its build quality, I think it should be a top contender in its price range and compared to Schiit Modius — which I also have — I definitely think SU-9 is a more detailed DAC and I actually do prefer it. I prefer the Modius over the M200 personally, but I think I prefer the SU-9 to the Modius, so really good job SMSL on the SU-9. It is
a very, very nice DAC with a lot of feature sets, remote, bluetooth, filters, sound modes, balanced output, very nice looking, very solidly built, so SU-9 absolutely gets my recommendation. It should be very high on your list in the sub-500 dollar DAC range.