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SMSL SU-1 Stereo DAC Review

Rate this DAC:

  • 1. Poor (headless panther)

    Votes: 8 1.7%
  • 2. Not terrible (postman panther)

    Votes: 9 1.9%
  • 3. Fine (happy panther)

    Votes: 59 12.6%
  • 4. Great (golfing panther)

    Votes: 391 83.7%

  • Total voters
    467

amirm

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This is a review and detailed measurements of the SMSL SU-1 stereo USB DAC. It was arranged to be sent to me by shenzhenaudio from the company and costs US $79.99.
SMSL SU-1 stereo USB DAC Review.jpg

Despite its simplicity, the SU-1 manages to look elegant with nice fonts and LED indicators for different inputs. Back panel has the basically what you want:
SMSL SU-1 stereo USB DAC back panel Review.jpg

My usual minor gripe applies here with right channel RCA not being red although in this case, it is easy to turn the unit around to plug in the cables. A USB-A to USB-C cable is provided. Note that you need to have a USB power supply even if you use non-USB input (it is the only source of power).

SMSL SU-1 Measurements
Let's start with our usual dashboard:
SMSL SU-1 stereo USB DAC Measurements.png

Very nice performance with respect to noise and distortion, easily landing it in our "excellent" category of DACs:
Best stereo cheap DAC review 2023.png


Zooming in:
Best stereo cheap DAC review zoom 2023.png

Full transparency is achieved not only for distortion but also noise:
SMSL SU-1 stereo USB DAC DNR Measurements.png


IMD distortion is basically non-existent with the performance limited by noise alone:
SMSL SU-1 stereo USB DAC IMD Distortion Measurements.png


Jitter shows some negligible spikes of no audible concern at all:
SMSL SU-1 stereo USB DAC Jitter Measurements.png


Multitone shows extremely good performance:
SMSL SU-1 stereo USB DAC Multitone Measurements.png


Linearity is almost perfect:
SMSL SU-1 stereo USB DAC Linearity Measurements.png


Filter attenuation is very good:
SMSL SU-1 stereo USB DAC Filter Measurements.png


Resulting in good wideband noise+distortion measurement:
SMSL SU-1 stereo USB DAC thd vs frequency Measurements.png


Finally, frequency response is essentially flat in audible band:
SMSL SU-1 stereo USB DAC Frequency Response Measurements.png


Conclusions
SMSL cuts the functionality to minimum many need to have high quality conversion of digital to analog from multiple inputs. Performance is superb for the cost as it provides full transparency to the source. It proves that performance requires great engineering skill, and not a ton of money. A lesson that I hope one day high-end audio companies and their customers appreciate.

I am happy to recommend the SMSL SU-1. There is no more excuse for having bad DAC performance!

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As always, questions, comments, recommendations, etc. are welcome.

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One more on the pile of evidence that DACs are a solved problem.
Until every DAC manifests that and comes with measurements to prove the same, we need to keep doing this....
 
When you think about it, it's incredible performance for the price !

Thanks for this review.

The frequency response slow slope is unusual. Strange.
I highly doubt it could be audible though, even by (very) young ears.

(And, maybe, if they remove MQA support, they could make it even cheaper ?)
 
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Ordered it right away!
Trank you Amir, I can update my signature now!
 
Simple but effective! Most people would probably want a remote & volume control included, but beyond that I can't fault it!
 

>Latest Generation XMOX XU-316 Processor.

>High-Performance AK4493S DAC Chipset.

>Supports High-Res PCM(32-Bit/768kHz) and DSD512 Audio Signals.

SMSL SU-1 _ SU1 High Resolution USB MQA Audio Decktop DAC.png
 
what a cute and clean little thing! is there dedicated amp?
 
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Conclusions
SMSL cuts the functionality to minimum many need to have high quality conversion of digital to analog from multiple inputs. Performance is superb for the cost as it provides full transparency tot he source. It proves that performance requires great engineering skill, and not a ton of money. A lesson that I hope one day high-end audio companies and their customers appreciate.
Find one typo.
tot he --> to the
 
Thanks @amirm !

This provides basically the same performance of the PO100 AK I re-measured. (probably the same circuit around AK4493 chip). Except S.M.S.L finally seem to have fixed the FR.

This is now a fawless single-ended DAC, with the digital inputs needed. At this price (89€ for EU MSRP)... heck of a bargain!
 
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I think this is as far as we'll have with "<$100 SOTA DACs". I truly appreciate the continuous improvements in this specific bracket, although for a big part of consumers in this price range they either won't care or expect too much.
 
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