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Review and Measurements of SMSL SU-8 DAC

amirm

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Not the filters but the sound profiles (Rich 1 2 3, Tube 1 2 3 , Crystal 1 2 3) are custom harmonic distortion "curves" created by SMSL taking advantage of the THD compensation feature of the ES9038Q2M chip.
The reviewer did't know this at the time of measurement, which makes me wonder if the problem with distortion at high levels shown in the graphs is somehow a cumulative effect related to this particular feature.
If you mean my review, that feature was off when I tested it.
 

Pillars

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If you mean my review, that feature was off when I tested it.
He's wondering if the feature's existence/implementation in itself may be causing the issue. Since it is software controlled who knows... I just don't run my SMSL SU-8 at max for my home theatre and I've not had issues. Still, I hope this is fixed and current owners are offered resolution. Highly likely the latter won't happen.
 
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If you mean my review, that feature was off when I tested it.
Thats nice to know, if you don't mind I have a question for you, at the time of measurement have you experienced an high pitched noise coming from the unit itself? (not in the signal).

I ask this because when I cold start my unit after being unplugged for a while, it starts making this high pitched noise inside (barely noticeable), until I restart the unit then it stops forever unless I unplug the main power again.

I don't know what is causing that, I also don't know if it's something related to other units or just mine, but if is related to other units than is it possible for it to be potentially the core of the problem shown in the measurements?
 

amirm

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Thats nice to know, if you don't mind I have a question for you, at the time of measurement have you experienced an high pitched noise coming from the unit itself? (not in the signal).
No, I didn't notice this. If they ever send me another, I will check for this.

I don't know what is causing that, I also don't know if it's something related to other units or just mine, but if is related to other units than is it possible for it to be potentially the core of the problem shown in the measurements?
I am doubtful. Mechanical noises can be from transformers and such and shouldn't impact electrical performance.
 
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No, I didn't notice this. If they ever send me another, I will check for this.


I am doubtful. Mechanical noises can be from transformers and such and shouldn't impact electrical performance.
Thanks for your reply.
I've tried it again right now. basically just turning the unit off, unplug and plug back in the power chord, turning the unit on, there's this weird noise from the unit which vary during startup and then stabilize, it stops completely once the unit is restarted.
If somebody could try on his unit and confirm what i'm experiencing would be nice!
 

Pillars

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Woah.. can confirm. Have to be close to the unit to hear but definitely does that. Quick reset and it goes away...
 

LarsS

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Thanks for your reply.
I've tried it again right now. basically just turning the unit off, unplug and plug back in the power chord, turning the unit on, there's this weird noise from the unit which vary during startup and then stabilize, it stops completely once the unit is restarted.
If somebody could try on his unit and confirm what i'm experiencing would be nice!
Coil whine, my Dell 1530 laptop suffers from this (known problem with this model)
 
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Coil whine, my Dell 1530 laptop suffers from this (known problem with this model)
Yes the sound reminds me to some sort of coil whine and might indeed come from the transformer, however the fact that it stops once restarted is very strange.. Seems like a cold start somehow doesn't properly start the unit.
 
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I am doubtful. Mechanical noises can be from transformers and such and shouldn't impact electrical performance.
If is this noise coming presumably from inductor or transformer and is only present during a cold start and goes away once restarted, could this explain a variation in electrical performance between the two states "cold started / restarted"?
 
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I've had mine on 24-7 since getting it a few weeks ago. It runs completely silent and I'm very impressed at the performance. Wonderful DAC, especially for the $$.
 
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Here are filters 1 through 7 response to white noise:

View attachment 14145
Thanks for taking the time to perform all the testing on this unit. Would it be possible for you to annotate the diagram to indicate which curve relates to which filter, or even break the plots out to different images? Unfortunately some of the colors are duplicated and it is very difficult to correlate the result with the applied filter.
 
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I will have to re-run the test. SMSL sent me a new one that I mean to test anyway and I will include it in that.
Fantastic! I'm selfishly hoping the first unit's balanced performance was anomalous. I am driving a pair of Adam Audio A7x's off the balanced outputs as well as a sub off the SE outputs in my living room. Subjectively, this unit performs as well as I could ever want/need, but having it measure better would be satisfying in the same way as having a car with a high top speed or lateral acceleration. Not relevant to my use case rationally, but emotionally gratifying.
 
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Amir,
If you have a chance to retest the balanced outs on the new SU-8 to see if there are any *positive* changes from the last time, please reply back to the thread. No graphs needed!!! Massdrop has the unit available again at its' regular $199 price until 11/30ish. Hoping on an improvment on one of the few affordable balanced DAC options out there.
 

amirm

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Amir,
If you have a chance to retest the balanced outs on the new SU-8 to see if there are any *positive* changes from the last time, please reply back to the thread. No graphs needed!!! Massdrop has the unit available again at its' regular $199 price until 11/30ish. Hoping on an improvment on one of the few affordable balanced DAC options out there.
Preliminary testing shows major improvement there. Go ahead and take advantage of the sale. :)
 
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Thank you @amirm ! My initial plan was to get a TOPPING DX7s during Black Friday Sale, if the SMSL SU-8 does have some flaw on XLR output. Now I can save a few bucks and hide them in my coach.Would love to save a little longer to get something with vast improvement like VMV D1.
 
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Amir,
Joined the drop. I have now spent close to $1k since joining this board...:eek: At some point I am going to have to stay away for a while...
 

amirm

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Amir,
Joined the drop. I have now spent close to $1k since joining this board...:eek: At some point I am going to have to stay away for a while...
:) There is always the music threads you can participate in. :)
 
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good...good!!!! Need alternatives. Looking forward to the updated specs/graphs on the SU-8, hopefully they will not come out w/a Black edition as the temptation to match the 789 will be hard to resist.
 
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