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SMSL SU-9n Review (Balanced Stereo DAC)

amirm

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This is a review and detailed measurements of the SMSL SU-9n balanced USB stereo DAC with Bluetooth support. It was sent to be my Shenzhenaudio and costs US $399.

From the outside, the SU-9 looks like the recent DACs from SMSL:

SMSL SU-9n Review XLR USB Stereo DAC.jpg


And from the back side for that matter:

SMSL SU-9n Review Bluetooth XLR USB Stereo DAC.jpg


A side story. When I started to test the SU-9n, I could not get one unbalanced channel working. I tried everything but one channel would not work. Balanced was fine. Later on I went to test the Coax input and it was then that I figured out that the "non working" channel cable was hooked up to the Coax digital input! I had hooked it looking from above and just assumed the RCA connectors would be next to XLR connectors.

Anyway, good to see in-built AC mains power supply despite the small form factor.

SMSL SU-9n Measurements
Starting with XLR balanced output, there was more output than my standard 4 volt so I adjusted the volume to get it close:

SMSL SU-9n Measurements Balanced XLR USB Stereo DAC.png


This is exceptional performance with distortion almost shrinking down to -140 dB! This places the SU-9 in #3 position of some 350 DACs tested to date:

Best stereo dacs reviewed.png


Performance using RCA out is almost as good:

SMSL SU-9n Measurements Balanced RCA USB Stereo DAC.png


Distortion is even lower but noise is a bit higher and hence slightly lower SINAD.

Since there is more output to be had at full volume, I ran a level sweep:

SMSL SU-9n Measurements THD vs Level Balanced XLR USB Stereo DAC.png


Performance keeps improving so if your amp can take it, let it go to max volume!

Dynamic range is superb:

SMSL SU-9n Measurements DNR Balanced XLR USB Stereo DAC.png


Linearity is exceptional:

SMSL SU-9n Measurements Linearity Balanced XLR USB Stereo DAC.png


Multitone performance follows the same:
SMSL SU-9n Measurements Multitone Balanced XLR USB Stereo DAC.png


Jitter performance is just as good with USB but there is a bit of jitter over coax:
SMSL SU-9n Measurements Jitter Balanced XLR USB Stereo DAC.png


Don't ask me about optical input. I sent out my Toslink cable to the store to get some milk and it has not come back....

I was surprised to see two new "Customized" filters in the already large set provided:


SMSL SU-9n Measurements Balanced Filter XLR USB Stereo DAC.png


I have no use for them though give the fact that they roll off early and don't cut out much. I looked in the manual but there is no documentation on them.

The filter choices makes a difference in THD+N vs frequency due to it measuring "out of band" spectrum of the DAC:


SMSL SU-9n Measurements THD vs Frequency Balanced XLR USB Stereo DAC.png


Lastly here is our IMD vs level:

SMSL SU-9n Measurements IMD Balanced XLR USB Stereo DAC.png


The classic signature ESS DAC chip IMD "hump" is there, albeit, very much reduced to be a non-issue.

Conclusions
Yes, yet another exceptionally good DAC. I know some of you are going to complain about us testing so many of them. Imagine if the situation was reverse and most of what we tested was junk. Would you be happier then? I don't think so. :) Count your blessing that you have so many choices and how barriers are being broken every few weeks and months in lowering noise and distortion.

I am happy to recommend the SMSL SU-9n.

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

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

KiyPhi

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Thanks for the review as always Amir. It seems they have a new remote but it also appears you can't control the other devices with this remote like you could with the old one. It was nice having one remote that controlled my DAC, headphone amp, and speaker amp. I suppose I could still get a programmable universal remote with the savings difference though.
 

aj625

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as one of the cheap topping smsl and gustards dac break the sinad barrier, many boutiuqe dac lovers feel more and more agitated and try to prove more and more vigorously that measurements dont matter or there is a limit of audibility of good measurements. the same thing happened in one of the dcs bartok thread in this forum elsewhere. almost all the posters were trying to justify the 110db sinad of $17500 DCS bartok. now a days even a well implemented ultra cheap dongle dac can beat these boutique dacs in terms of measurements. it is so surprising how such boutique dac manufacturers are able to brainwash so many people that they dont want to listen anything against these boutique dacs at all. may be its the money power through which the manufacturer propagate many subjective lies on all type media platforms
 

tw99

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as one of the cheap topping smsl and gustards dac break the sinad barrier, many boutiuqe dac lovers feel more and more agitated and try to prove more and more vigorously that measurements dont matter or there is a limit of audibility of good measurements. the same thing happened in one of the dcs bartok thread in this forum elsewhere. almost all the posters were trying to justify the 110db sinad of $17500 DCS bartok. now a days even a well implemented ultra cheap dongle dac can beat these boutique dacs in terms of measurements. it is so surprising how such boutique dac manufacturers are able to brainwash so many people that they dont want to listen anything against these boutique dacs at all. may be its the money power through which the manufacturer propagate many subjective lies on all type media platforms
No, they were mainly arguing with your assertion that the -110db harmonics were causing a “bright sound”.
 

xykreinov

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as one of the cheap topping smsl and gustards dac break the sinad barrier, many boutiuqe dac lovers feel more and more agitated and try to prove more and more vigorously that measurements dont matter or there is a limit of audibility of good measurements. the same thing happened in one of the dcs bartok thread in this forum elsewhere. almost all the posters were trying to justify the 110db sinad of $17500 DCS bartok. now a days even a well implemented ultra cheap dongle dac can beat these boutique dacs in terms of measurements. it is so surprising how such boutique dac manufacturers are able to brainwash so many people that they dont want to listen anything against these boutique dacs at all. may be its the money power through which the manufacturer propagate many subjective lies on all type media platforms
If we could hear differences in audio quality as easily as we can see differences in image quality, the audio industry would be very different.
Could you imagine if people claimed there's something special about flagship LCD displays from 2004 with pastel color gamuts, black levels the shade of a wet white sock, and pixels that transition by the time you're done cooking a grilled cheese sandwich? Everyone would think they're nuts.
 

SaltyCDogg

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Have SMSL reached out about sending the matching DA9 amp for testing? Or do they know it won't test well by ASR standards so they only send the DAC.
 

JSmith

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Have SMSL reached out about sending the matching DA9 amp for testing?
Fair question... maybe that review is coming next. ;)
Or do they know it won't test well by ASR standards so they only send the DAC.
This is a bit much... why make such a negative assumption based on nothing?



JSmith
 

aj625

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If we could hear differences in audio quality as easily as we can see differences in image quality, the audio industry would be very different.
Could you imagine if people claimed there's something special about flagship LCD displays from 2004 with pastel color gamuts, black levels the shade of a wet white sock, and pixels that transition by the time you're done cooking a grilled cheese sandwich? Everyone would think they're nuts.
see its always better to be guided by something objective than subjective things. you can see the effect of asr measurements these days. there are lesser subjective glowing reviews these days than few years back when asr was not there. people now are aware of getting exposed by the actual measurements. "there is no magical trick which can make poor measuring equipment sound better than better measuring equipments" if improved measurements are not linked with improvements to sound quality then does it mean sound quality over the years has deteriorated ?
 

SaltyCDogg

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Fair question... maybe that review is coming next. ;)

This is a bit much... why make such a negative assumption based on nothing?



JSmith
I didn't think it was a particularly strong suggestion (rather than a statement). It appears to be extremely hard to make a well measuring amp with a remote, display and features for this sort of money. We've a few threads on here for products like the DA9 and SA300 with hundreds of responses but little measurement. I own the SA300 and think it sounds pretty good, but I'm unconvinced it will measure well.

That's why people are getting excited about the amp Topping are teasing
 

JSmith

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bidn

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FYI for those of you who are MQA haters -- you know you are -- that has been deleted from this DAC.

Thank you very much for this excellent news, in addition to your excellent review of this excellent DAC!
I hope this will go on like this with future DACs.

BTW, "MQA haters" is how MQA people call critics. I am, and I think it is the same for the others, just someone who loves high fidelity, unmessed audio, honesty, openess, freedom, truth and unfortunately sees the opposite with MQA.
 
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