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SMSL SU-8s Review (Balanced Stereo DAC)

amirm

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This is a review and detailed measurements of the SMSL SU-8s Balanced USB Stereo DAC with Bluetooth input. It was sent to me by shenzhenaudio and costs US $360.

The SU-8s is typical of the later desktop products from SMSL:

SMSL SU-8S Review Balanced USB DAC Stereo.jpg


Pushing in the volume control shows the menu options. A remote control is also provided (which I did not need to use).

Back panel is as you would expect:

SMSL SU-8S Review Balanced back panel USB DAC Stereo.jpg


Nice to see in-built AC power supply to reduce desk/wall clutter.

SMSL SU-8s Measurements
Let's start with our usual dashboard of 1 kHz tone at full volume measuring balanced output first:

SMSL SU-8S Measurements Balanced USB DAC Stereo.png


As expected, performance is excellent, stopping just a hair from the best there is:

Best balanced stereo dac review.png


And landing in our top 20 best DACs ever measured:

Best balanced stereo dac tested.png


Unbalanced RCA output produces nearly the same performance:

SMSL SU-8S Measurements RCA USB DAC Stereo.png


Dynamic range is top notch:

SMSL SU-8S DNR Measurements Balanced USB DAC Stereo.png


Dual-tone IMD tests shows a hint of ESS "IMD hump:"
SMSL SU-8S IMD Measurements Balanced USB DAC Stereo.png


Linearity is perfect:

SMSL SU-8S Linearity Measurements Balanced USB DAC Stereo.png


As is multitone:

SMSL SU-8S Multitone Measurements Balanced USB DAC Stereo.png

There is just a trace of interference with USB input in our jitter test:

SMSL SU-8S USB Jitter Measurements Balanced USB DAC Stereo.png


That gets a bit worse with Toslink/Coax:

SMSL SU-8S USB Toslink Coax Measurements Balanced USB DAC Stereo.png


We have three filters to choose from:

SMSL SU-8S Filter Measurements Balanced USB DAC Stereo.png


I like the minimum phase one which produces this excellent THD+N versus frequency:

SMSL SU-8S THD+N vs Frequency Measurements Balanced USB DAC Stereo.png


Conclusions
We are so luck that despite the low cost of these devices, they continue to compete with each other to squeeze the last bit of performance. There is just really no fault to put your finger on.

I am going to put SMSL SU-8s on my recommended list.

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

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Tks

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Any word on how the Bluetooth performs? Even just a basic measurement out of Roon by proxy?
 
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mslim

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Thanks. There's some many "equals" now the features hardly differentiate them apart; it primarily looks to come down to cost and (product) support.


1. I have issues with using OLED for such products due to the burn in. Can this be totally turned off?

2. The main competitor is Topping D30Pro - hope there will be a price squeeze here but hard to beat the Topping E50 unless you want built-in power.

3. Topping D30Pro got that funny noise thing in Amir's tests. Not sure the effect of this.

4. No IMD hump with some measurable noise vs hump with no noise.....

5. This if you want bluetooth....
 

ShiZo

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This thing is amazing past that little rise in IMD. I'm sure it's not audible... Damn I'm a snob.
 

abdo123

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The ESS hump is much more controlled than ln the SU-8.

The only way I know of to control the ESS hump completely is to raise the noise floor so the distortion is submerged with noise.

So yeah, in the era of SINAD and ASR, engineers would rather have a higher ranking device than a more linear behaving device.

I mean don't get me wrong, it's not Amir's fault in anyway, and he is already providing above and beyond most people in the industry, but it is what it is.
 
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ShiZo

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The only way I know of to control the ESS hump completely is to raise the noise floor so the distortion is submerged with noise.

So yeah, in the era of SINAD and ASR, engineers would rather have a higher ranking device than a more linear behaving device.

I mean don't get me wrong, it's not Amir's fault in anyway, and he is already Amir is providing above and beyond most people in the industry, but it is what it is.
I wouldn't have minded a little more imd for it to be linear. I think it is still best bang for buck right now.
 
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VintageFlanker

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Many thanks, @amirm!

One question, tho: the SU-9 was able to deliver 5.3Vrms output at max volume (and max SINAD), making it an ideal choice as a capable preamp.

What about this one?

Edit: my bad, it says 4.05V measured at "full volume".:facepalm: So, this is basically a cheaper SU-9 with less output voltage. The ESS Hump is also fairly contained and not that big of a deal...
 
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DSJR

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Looked to see if it was available in the UK yet but was sidestepped into a headfonia review which in the link hinted at an objective test but in practice was a subjective one. Not sure how 'more aggressive but more natural in tone' quite come together. Amazing that all these dacs 'sound' totally different apparently and of course the more expensive ones always 'sound' better... (Been there and done it all decades ago folks and sort of came out the other end rather jaded now ;) )
 

renaudrenaud

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Looked to see if it was available in the UK yet but was sidestepped into a headfonia review which in the link hinted at an objective test but in practice was a subjective one. Not sure how 'more aggressive but more natural in tone' quite come together. Amazing that all these dacs 'sound' totally different apparently and of course the more expensive ones always 'sound' better... (Been there and done it all decades ago folks and sort of came out the other end rather jaded now ;) )

Man, this is the business model!
 

jokan

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The BT AptX Lossless is expected to hit product shelves next year, as in equipment that will have AptX Lossless built in.
I wonder if a firmware update will allow for the lossless capability though I doubt it highly. It would be nice to have something better than what is available as I guess I am a snob and don't like lossy formats as a generalisation. I know that it will progressively reduce it's bandwidth depending on the environment, so I would assume walking into a shop with a tonne of bluetooth devices already active will cause drop-outs. I hope Sony allows for AptX Lossless in their next iteration of their noise cancelling WH-1000XM??? model. I've had 3 generations of the series of headphones and am very happy with them, but am always stuck on the fact that they are indeed lossy though I can go wired and activate the Sony EQ which is pretty much necessary to make them sound reasonable. Technology, we can't fight the progress but I wonder when our human ears become redundant. Surely that's not far off in the future. Definitely not likely in my lifetime, but possibly?

I am very impressed by the SU-8. I am waiting for the Aoshida version of the same device and I have been told that it's already in development, undergoing final testing. Should see it drop soonish!
 

Madjalapeno

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Thanks. There's some many "equals" now the features hardly differentiate them apart; it primarily looks to come down to cost and (product) support.

And appearance. When they get some nice industrial design things will get real interesting.
 

Doodski

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Thanks. There's some many "equals" now the features hardly differentiate them apart; it primarily looks to come down to cost and (product) support.
The issue with the cost is the per unit price and what that means to the manufacturer or supplier. They need to maintain a certain gross cost to make it worthwhile to offer.
 
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