SMSL SU-9 Review


DAC Performance

The signature is quite balanced with a slight hint of warmth. The SU-9 has an effortless and airy presentation across the spectrum. Technical capability roused my excitement as soon as I heard it. It sounds resolving and detailed, maintaining a perfect balance between sounding analytic and smooth. It is not a nit-picking DAC, it is not exactly forgiving either. It wants you to match it with good equipment and find a good synergy. If you pair it up with a reference, flat gear, they make quite a transparent couple. If you pair it with a warm headphone, such as the good old HD-650, you get a nice and smooth but also a detailed presentation.

In my opinion, the overall sound quality is quite satisfactory. The low region has enough impact to make you tap your toes with Michael Jackson’s ”Bad” the authority is very good as well as the texture. The midrange is clear, defined, and articulate. It does not have a light note-weight or excessively thick one. SMSL tuned it to stay in the natural range. Saturation is out of the equation and the DAC does not color your gear’s signature. The upper midrange is breathy with a focus on clarity. Treble extension is brilliant and tuned very well. Listening to Nina Simone’s ”Sinnerman” with the Velvet V2 and the SU-9 | SH-9 stack is a euphoric experience. The wide stage does help with the dispersion of the extension of the highs and does a really good job here. That and brilliant instrument separation results in holographic imaging that we audiophiles long for. PRaT is equally impressive and especially with the SH-9, it takes the SU-9 to whole another level. The SH-9 is a flat, colorless amp that has very good dynamics so pairing it with the SU-9 results in a very fast, prat-wise quick, and agile presentation. Nicely done.

Sound Color Options

As I mentioned in practically every section, the SU-9 comes with an ESS9038PRO DAC. This particular DAC has a DSP that you can control via device settings. There are 3 options here. Rich, Tube & Crystal. As can be deduced from their names, these modes do have a slight impact on the color of the sound signature. Rich mode provides a smoother signature, where the upper midrange and highs are affected the most. Also, the note-weight is slightly thicker in this setting. The tube setting provides an overall smoother sound but it is subtle and I didn’t quite like it. I think if you’re aiming for a smoother sound, you’re better off with the Rich setting instead of Tube. Lastly, the Crystal setting increases the upper mid sharpness and treble extension, which I believe is adequate without this setting. If you’re pairing the SU-9 with active speakers that have a warm signature, you can try toggling this to give them a more spacious and airy presentation. I mostly used the SU-9 in the standard-setting where the DAC bypasses all of these modes. 



I will be quite direct here. You should be using the XLR out. It’s that simple. The measurements are better, and according to my ears, the background is darker and clearer. Going fully balanced (from DAC to AMP to IEM/Headphone) results in clearer dynamics and better congestion handling. Plus, if you’re going to use the SU-9 with a computer, you should opt in for the XLR for sure as the signal will be much less affected by all the noise your rig may add into the equation. You will get a lower noise floor so this translates into a better Signal-to-Noise ratio. This is especially important if you have a custom-pc like I do, as they tend to be even noisier, electronically, compared to a laptop.

SMSL SU-9 & SMSL SH-9 Stack Performance

Naturally, SMSL designed these two as a stack and they did one hell of a job with both of the units. The SH-9 will soon be reviewed on so stay tuned in. Before that, let me give you a little what-to-expect paragraph. The SH-9 is a flat, colorless THX AAA-888 amplifier with a very impressive spec sheet. It is powerful, it is capable and it is the perfect match to the SU-9. Not only physically but sound-wise as well. It does a great job of polishing what is already great about the SU-9. Together, they make a coherent, articulate, and resolving couple. Clarity is top-notch. They should be used in fully balanced for maximized potential. I really did enjoy this stack with Sennheiser’s 660S. The presentation was very spacious, exciting, and dynamic. The resolving signature of the SU-9 is enhanced and complemented by the SH-9 very well. Tight, fast, and agile bass response with a sweet midrange and a clear treble, that’s the recipe. Combine this with a spacious staging and you’re golden.


Last Words

The SMSL’s SU-9 is a very capable DAC with a killer price to performance ratio. It supports MQA natively and can be used wirelessly thanks to its HiFi-capable Bluetooth 5.0 chipset. You can hook it up to your active speakers and stream Tidal MQA. You can control the unit via the remote for convenience. The build quality is, as always with the SMSL, perfect. There are no imperfections on my unit’s casing and I have never experienced a problem with an SMSL before.

They make good, value-for-money products, and this one, in particular, is a performer. You can get an SH-9 for a perfect match and go fully balanced to utilize their maximum potential. I highly recommend you to do so.


4.3/5 - (147 votes)


Long time Tech Enthusiast, an ambitious petrol-head, Yagiz likes his gadgets and always finds new ways into the tinkerer's world. He tries to improve anything and everything he gets his hands onto. Loves an occasional shine on the rocks.


  • Reply March 11, 2021


    A really nice review and interesting to hear that it has slightly warm tint. Might be a good match with my HD800. Do you have any plans to look at the Gustard X16? Similar features, measurements and price but seems to be getting less coverage than the SU-9.

    • Reply March 21, 2021


      Yes, we have plans to cover the x16 soon, let’s see how it holds up against this one. We are also going to review the Topping D70S.

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