S.M.S.L SU-9

General Information

Support MQA full decoding:
Clean up the recording

When the analog sound is converted to a digital signal,time blurring will occur,blurring transient signals over time. As a result, our ears cannot tell where a single sound comes from, the comparison between recorded music and "live performances" is unremarkable! MQA can eliminate this distortion and create a true 3D sound field, which is different from any sound you have ever heard.

Encapsulate the sound
1.MQA Decoder
This will expand the MQA file once to provide better sound quality than CD quality.Products with MQA decoder has Bluesound, Pioneer and Onkyo's player (with a digital output product).Such as shrimp and music streaming service providers and Roon other media player.

2.MQA Renderer
Use the product with MQA renderer to complete the final deployment. Renderer including USB DACS and some headphones and other portable products.For example, AudioQuest DragonFly can connect to the MQA Core signal and complete the expansion of the MQA file.

3.MQA Full Audio DAC
Products with MQA full decoder can fully expand the file to provide the best sound quality.Playing at this level, you will hear theoriginal sound created by the artist in the recording studio, with precise files andspecific DAC compensation and management.

Input: USB/Optical/Coaxial/Bluetooth
Dynamic range:XLR 130dB
RCA 123dB
Output impedance:XLR 207Ω
RCA 142Ω
USB transmission:Asynchronization
USB compatibility:Windows 7+,Mac OSX,Linux
Bit depth: USB 1bit,16-32bit
Optical/Coaxial 1bit,16-24bit
Sampling rate: USB PCM 44.1-768kHz
DSD 2.8224-22.5792MHZ
Optical/Coaxial PCM 44.1-192kHZ
DSD dsd64(DoP)

UAT:24bit/192kHz (1200kbps/900kbps/600kbps)
LDAC:24bit/96kHz (990kbps/660kbps/330kbps)
aptX-HD:24bit/48 kHz-576kbps
aptX:16bit/44.1 kHz-352kbps
SBC:16bit/44.1 kHz-328kbps
AAC:16bit/44.1 kHz-320kbps
Power Consumption:5W
Standby power:<0.5W
Size:187.5X154X40mm (WxHxD)

Contents List:
USB cable*1
Power cable*1
User guide book*1


Latest reviews

Pros: Fantastic sound. Easy to use UI. Flagship ESS DAC. Balanced DAC.
Cons: May be a bit warm sounding for some.

I started out my audiophile hobby using portable DAC/amps since those were a little more multipurpose for my needs and easier on the wallet at the time. After deciding to jump into the rabbit hole after some time I decided to bite on a desktop setup. I, like many others, initially bought a modi/magni stack to get started. This worked out fairly well but the audio upgrade bug eventually rears its head and demands money for new gear. I went on to buy the atom amp then decided I wanted to try this whole balanced thing. This led me to buying the v2 SMSL SU-8 and SH-8. Having a balanced setup and a higher quality dac really changed a lot of my views on audio gear. I went two years on that SMSL stack and dedicated my money to headphones and other audio gear. When they announced a SU/SH-9 stack was on the way I had to see if the new stuff was worth almost twice the price of the old SMSL stack. This first review will cover the SU-9 with a SH-9 review coming out shortly after. The SU-9 is running an ESS ES9038 pro DAC chip and has the option for MQA decoding and rendering. The SU-9 as of this writing comes in at $440.

Thanks to ShenzhenAudio for hooking me up with a review unit. While I always appreciate stuff being sent in to test and review, It never affects the ratings of my reviews.

More info on the SU-9 plus the purchase link will be below!

Gear used

IPhone 12 Pro via usb, SMSL SU-8, SH-8/9, Schiit heresy , Ikko OH10, Campfire original andromeda, ADV M5-5D,LCD2C and Dan Clark Audio Aeon flow “RT” closed.

Looks and Feel
I like the more grown up look of the SU-9 over the now old SU-8. It goes from an almost MacBook silver finish to an all black unit with a good sized screen. Running through the menus of the SU-9 is a pleasure and I like the layout as well. I enjoy that they still use an internal power supply vs having a brick hanging off the back. This of course means you don’t have a crazy wide power plug to plug into a wall or strip. The included remote is the same as the SU-8 remote and I enjoy the ease of use for that as well.

Accessories and unboxing
The box is inside a sleeve and when you open it up and toss the top foam layer out, you’re greeted with the unit wrapped up, the power cable and a USB cable. The USB-A cable isn’t as nice IMO as the one that came with the SU-8 but it’s fine for getting the job done. A little QA card and manual are included.

The UI is fairly simple and since I’m somewhat late to the review party I’ll skip going over every option in the menu system and just go over the things I felt were neat. There’s an option the have a fixed output volume or variable which is nice, the common ESS sound color and PCM filter options are there. I honestly can’t tell the difference with those so I did apodizing for the filter and standard for the sound color like my SU-8. Then lastly there is an option for jitter reduction. I don’t believe it’s a problem for usb and so I set that down to minimum and went on with my life haha.

The SU-9 claims it can do the decoding and rendering of MQA streams which I can verify is true. When choosing the SU-9 as a decoder you will see a little blue or green dot next to the MQA logo depending on the recording. If you use it as a render from say something like an iPhone, it will swap over to a magenta color to indicate streaming. I honestly can’t tell the difference between a good quality file vs MQA but it’s always nice to have the option. It’s fairly quick to bite when moving to different parts of a track. Though it’s a little slow on 24/96 tracks.

I had no issues with range in my apt when connected to my iPhone. I didn’t try the FiiO M11 with Bluetooth since I personally don’t have a real need to use Bluetooth when I’m next to my computer. The iPhone only did AAC over Bluetooth and I had no issues with connections breaking when I sent my roommate off with my phone while I had my door shut.

These will be my impressions overall with the SU-9’s sound signature when used with all the gear I threw it at.

Lows are fairly good no matter what amp I throw it at. I was worried it might sound lean or overshadowed by treble since this was a good measuring DAC. I’m happy this wasn’t the case. While the low end isn’t super boosted, it’s definitely a little more impactful sounding than a dead flat sounding DAC and there's good quality to the low end as well.

The mids sound very clean and clear overall. There are fantastic details in the vocals and instruments as well. There isn’t anything strange going on here which I enjoy as mids aren’t usually my huge focus but I still enjoy some quality mids nonetheless.

The highs are done really well with the SU-9. Detail retrieval and overall sound quality is mostly fantastic. Things do get a little hot at times depending on the amp and iems/headphones I’m using but this is mostly the sss/shh sounds in the lower treble. Some things sound a little different and almost strange and artificial on some types of top end sounds. Fairly rare but with some tracks this was most noticeable when plugged into either the Schiit heresy or the SMSL SH-9. Both being brighter amps might be the reason I’m hearing this possibly. I actually didn’t notice this with both amps when listening to the same track with the now old SU-8.

Amp selection will be the biggest factors in this area but when the SU-9 is paired with just the right amp you get some really nice depth with an above average width. Imaging across all amps I tested with was fantastic and I had no issues with my side to side sound sweeps or picking out where things were located when listening.

Inputs and outputs
You get the option for usb in, optical in and coaxial in. I had no issues with both the optics and usb inputs. I didn’t try the coaxial as I just don’t use/have any gear with that output. You also get a balanced XLR out and single ended RCA out for plugging into whatever you want. I had zero issues with the outputs as well.

Amps pairings


The SH-8 is a fairly warm amp, the SU-9 doesn’t do much to fix this but it does bring out a little better detail retrieval and it’s easier to pick out micro details as well. Stage continues to be wide with the depth sounding a bit better than the SH-8 normally sounds off other sources. If you already had the old SMSL stack and were thinking about swapping just the DAC to squeeze out a little more detail, then this is still a good choice. If you had the SH-8 and wanted to brighten it up without using the onboard EQ then you will want to look at another DAC.

This was my favorite paring. The SH-9 paired with the SU-9 made for an extremely accurate sound but it still had a dynamic low end without feeling too warm sounding. Soundstage width is average but the depth is fairly deep sounding to my ears. Imaging was very good with this combo as well. This would be my recommended pairing. Unfortunately I don’t have any of Topping’s amps to test. So take this recommended pairing as you will.
IMG_4704 (1).jpg

Schiit Heresy
One might be asking “Why would this man who loves corgis mention pairing a $440 DAC with a $100 amp?”. I don’t believe everyone will be buying both this and the SH-9. For those who may have a Heresy or another $100 amp might be wondering if upgrading a DAC first before an amp makes sense or not. To that I would say kinda. A lot of the issues I have with the Heresy sounding compressed at times is still a problem when paired with the SU-9. The detail retrieval is still fairly good but it still feels like the biggest bottle neck to the sound is the amp itself. Where I found the Heresy fairly clinical and lean sounding when plugged into the SMSL SU-8 and iFi NEO, it’s a little brighter on the SU-9. The SU-9 gets a little hot up top at times depending on the amp and the Heresy is one of those. It’s fine with some of my warmer headphones and iems but a no go for most of my gear.

Dac comparisons
I had planned to compare this to other DACs but the ESS DAC used in both the SU-8 and SU-9 are on the warmer side compared to other ESS DACs so I’ll just compare the two.

Both the SU-8 and SU-9 are on the warmer side vs other DACs I’ve used recently and in the past. The bigger difference between the two DACs IMO are detail retrieval, soundstage and slight feature differences. The SU-8 has a wide sound but has a rather close feeling with less depth. The SU-9 has the opposite and feels deep with an average width. This of course was with the three amps I tested with. Detail retrieval was a small step up in the new SU-9. I still find the SU-8 a fantastic DAC but you can tell just a little more is getting squeezed out of the SU-9 in terms of detail retrieval as well as small micro details. The bigger thing that might be considered for an upgrade or picking between the two would be the easier to use UI on the SU-9 due to the screen, MQA support(if you want it) and Bluetooth which the SU-8 is missing.

Overall thoughts
Even though the new SU-9 is $190 more than the SU-8, I really enjoyed the added features and sound quality upgrade it provided. I think the SU-9 will pair extremely well with any type of amp and I also find this to really be a good sweet spot for most users. There’s much more expensive DACs out there of course but it’s hard to beat the SU-9 overall IMO. I found the SU-9 paired with the SH-9 to be my favorite combo sound wise. Plus I like the way the stack looks. I can easily recommend the SU-9 for those looking for something that breaks into the mid-fi gear and possibly an end game DAC for most people. I’m very impressed and look forward to what SMSL brings out next. Thanks for reading!
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Thanks for your kindly objective review. Hope the SU-9 meets all of your requirements. :relaxed:
S.M.S.L SU-9 Review
Pros: Excellent resolution
- Holographic and accurate sound stage
- Neutrality
- Supports every Bluetooth codec (+UAT)
- Digital display
- Overall timbre is remarkable
Cons: A bit pricey from its predecessor
- Old school UI

Foshan ShuangMuSanLin electronics Co., LTD or S.M.S.L audio was established way back 2009 in Shenzhen China , their forte are DACs, stereo headphone amplifier, and power amplifier, and they have their very own R&D, manufacturing and marketing team. They are very famous as they sell a lot of good products with very attractive price tag.

Checking out their website, it is filled with sufficient details about their company and products, they aren’t one of sketchy Chinese companies that doesn’t have their very own website, they even have a detailed timeline as well as page dedicated for their certificates and awards. It may sound irrelevant but having a decent website makes them much more reliable.

The S.M.S.L SU-9

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-8 comes with ESS ES9038Q2M DAC, with 32-bit HyperStream II architecture, improving sound quality and DoP function. During its time, it is the latest DAC from ESS, same thing with the SU-9. 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.

Technical Specification:

Construction and Appearance

The S.M.S.L SU-9 comes with CNC milled full aluminum casing just like the SU-8, there’s actually nothing special about that but there’s also a TFT display for navigating the DAC, the remote included might not be perfect for navigating the SU-9 but it is sufficient and is truly ergonomic compared to its predecessor. 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.


What we can see in these pictures is that 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.

I love gears with midcentric to flat sound signature as I really love listening to vocals rather than instruments. My genre ranges from heavy rock, alternative rock, pop rock, acoustic, pop, jazz and folk. Majority of my test tracks are in 16 bit – 44 khz and 24 bit – 48 khz FLAC file and here is the list of my commom test tracks.

  1. Reese Lansangan – For the Fickle (Background, female vocals and upper mids)
  2. Billie Eilish – wish you were gay (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Micro details)
  3. Rex Orange County – Untitled (Mid Bass, Mids)
  4. Ed Sheeran – Dive (Mid bass, Lower Mids)
  5. Reese Lansangan– My Sweet Hometown (Upper Mids and Instruments)
  6. Polyphia – Goose (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Treble)
  7. Utada Hikaru ft. Skrillex – Face My Fears (Imaging Layering, Bass, Mids, Treble, Coherence, Quickness)
  8. Polyphia – 40 oz. (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Treble)
  9. Polyphia – GOAT (Imaging, Layering, Coherence, Sub bass and Mid bass, Mids, Treble)
  10. Ariana Grande – Raindrops (Background, Upper mids)
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 seems to share the same fate with the former, I’m truly fond of female vocals and my music library proves it so much, I’m quite surprised with what I heard, the upper midrange 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. To keep it concise (because my review is too long already), I can say that it is neutral and can pair well with almost any gears out there, it is tuned quite safe and can actually please most if not all audiophiles out there since there is still good amount of body despite its resolving nature.

iFi Micro iDSD

Some might say that this comparison is unfair because the SU-9 is DAC only and is purely desktop equipment compared to the portable iFi micro, but considering the price and my experience with DACs, I think it is still good to compare these two great device. The iFi micro is noticeably wamer and it has thicker timbre compared to the more analytical SU-9. Bass feels deeper and more emphasized with the micro, while it is quicker with the SU-9, both have great extension while the SU-9 sounded more textured and refined. The midrange of micro has a more lush presentation with thicker vocals and instruments, again the SU-9 sounded more transparent and detailed compared to the micro. Lastly, treble seems to be a one sided round with SU-9 having the upper hand, it is just more extended, detailed and faster than the micro.

Topping D10s + Cayin C5

The SU-9 is priced more than four times the price of the D10S and that’s fine cause we’re losing a lot of features and raw specs from the former, but sound-wise (single ended) I wouldn’t say that they are 4x or even 2x away from each other. The bass of D10s is more flat and is thinner in timbre, it lacks extension as well, it isn’t as detailed as the SU-9 too but the difference is minimal. Midrange goes to SU-9, but the D10s is as flat as the SU-9 with less details and I think that is really impressive. Lastly, treble also goes to SU-9 by a notch, the D10s has less extension, details and is just smoother overall.


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.

Kinera Freya

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.


Honestly, desktop DAC aren’t my specialty since I’m more fond with portables ever since I started with this hobby, it is less costly and offers mobility. 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.
Thanks for the first SU-9 review on head-fi. :thumbsup:
great review. How does it compare with M400?


I just pick this one up also and pretty amazed at the quality of the bass and smooth mids with very good soundstage,voices sound so nice.Highs were not as detailed as my other unit but that cost 5x more and no MQA.I was wondering Im using a streaming unit connected to the SU-9 How do I control the volume using the streaming unit and bypass the volume on the SU-9?.