SMSL DO400 Review

Sound performances

For this review, I picked my old Audeze LCD-X and Audeze LCD-3, the all-new HiFiman Svanar, and the mighty Beyerdynamic DT900 Pro X, a good setup that should fit all genre and needs.

As for the source, music was streamed directly from my computer with Apple Music (Hi-Res), my own Plex library (Hi-Res), and Spotify (Lo-Res)

Overall signature

So, how’s that new SMSL DAC performing? Superb, as expected!

Signature-wise, the SMSL DO400 continues the trend set by the DO200 and DO200 MKII, featuring a neutral tone that prioritizes dynamic range over any sound coloration. This rendering is starkly different from that of my Cayin i-DAC6, but it’s an approach that I find absolutely captivating.

Once more, the DAC is dead silent, with pitch-black background, whatever the input I used. I mostly stuck with the USB ports, but even when connected as a Bluetooth endpoint, the DO400 delivered a flawless signal and allowed the music to shine, especially on Hi-Res track. Paired with the LCD-3, the combo exhibits the same behavior I found on SMSL previous setup: exquisite detail retrieval, with fast decay and rapid transients, with that usual flat/pro tone you expect from the brand. 

It’s sweet when needed, hard when you want it and, I’d even dare to say that SMSL is now reaching RME soundcard render, making the DO400 a solid alternative for anyone in need of a prosumer solution – especially with an XLR-EBU input available. With crisp highs, deep lows, perfect layering, and a wide soundstage, the DO400 ticks all the right boxes once again, and head-to-head against the old version, the difference is quite obvious, especially at mid-high volume.

Switching up to the DT900 Pro X, the difference was even easier to spot, with sharper low-mids and exceptionally swift transients, even on Spotify. On The Weekend – Funk Wav Remix, the pan-effects were almost too accurate, giving an uncanny feeling of wideness, making me almost dizzy. 

And, once again, if I couldn’t really grasp the differences between the three roll-off settings, playing with the sound-color settings appeared to be quite effective. The tube mode in particular happened to warm up the sound by a few degrees, emulating the peculiar render of vacuum tubes quite brilliantly. On the other hand, the crystal effects were a bit too bright for my taste, but maybe some of you will like this extra crispness – while I didn’t.

For those asking, I didn’t hear any difference between line and pre output, once I maxed out the volume, but there’s a clear improvement going balanced with some XLR plugs. First comes power, then follows depth and, quite honestly, I see no reason to use unbalanced connections with this device, unless absolutely necessary. In balanced mode, the stereo panning effects feel more natural, the nuances are more pronounced, and the dynamic range is so expansive that even my KEF speakers sounded like new.

On my usual electro tracklist, paired with the Sennheiser HD-800S, the combo outputs good headroom and hard-kicking lows, even at low volume. I could immediately hear the enhancement on You Make My Life A Better Place from the Mammas Gun, a small ring only heard on high-grade stack was also found here. And, if my Cayin IDAC-6 sounds more “natural”, head-to-head the SMSL was able to deliver more punch and more air, outperforming the DAC in both dynamic and distortion level, for half the price.

I also paired it with the old-but-mighty ALO Audio Studio-6 – an amp that I bought a few years ago now – and was pleasantly surprised to see how new, and old blood, match quite splendidly. SMSL found the sweet spot between accuracy and musicality, displaying exceptional resolution with the ALO, giving me – up-to-this-date – one of the best results I ever heard.

Overall, an exceptional performance!

Tonality

The sound signature is linear, but each frequency range has flaws and qualities—a quick overview.

Bass: deep, fast, accurate. The DO400 managed to reach deep notes with ease on my LCD-X and, paired with ALO Studio 6, the combo was almost equal to some of the best desktop setup I’ve tried this past month. Clearly, in this price range, the  SMSL manages an awesome job and with planar headphones, the result is amazing!

Test track : Ylang Ylang – FKJ

Mids: flat and clean. Good dynamic range combined with exceptional accuracy and absolutely grain-less/flawless background make the DO400 unsurprisingly good in this regard. That said, its most impressive feat remains how musical it sounded, even with difficult tracks, the small DAC out matching many of its competitors, with an equally detailed sound tainted with a delicate sweet touch.

Test track : Customer is King – Meute

Highs: straight and technical. If everything seems flat to my ears, some might find the SMSL DO400 a bit too conservative. But, the DAC shows excellent control and definitely exceeded the DO200/DO200MKII in this regard, even outperforming the Cayin or my HiFiman RE-400. Kudos! 

Good test track : Omnia – Anyma

Conclusion

Once again, SMSL amazed me with a wondrous device, exceeding all my expectations, at a price that sounds almost too low to be true.

If the DO200MKII was already great, the new SMSL DO400 is nothing short of exceptional, packing enough power to drive all my headphones, while maintaining a level of sonic refinement I didn’t think possible in this price range before.

Build quality is excellent, I/O is amazing, and either as a pure DAC or a DAC + preamplifier, the device is just flawless – especially now that SMSL fixed the lousy scroll wheel. Sure, you may find better, but for less than $500, or even $1000? I don’t think so.

An instant recommended buy!

 Pros

• superb sound and powerful output level
• incredible dynamic range and inaudible noise
• extensive I/O with HDMI, USB, XLR 4-Pins, Pentaconn 4-Pins etc…
• improved scroll wheel and great build quality
• amazing performance/price ratio

Cons

• sound signature a bit too linear for some genre
• not what you could call “sexy”