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SMSL M500 DAC Only “Thermal Issue” not “Golden Sample”

This should be a new reference chart to include in all future reviews. Starting with the DAC at room temperature and playing over 1 hour or so.

It adds an hour to every review. Ouch. But in real terms, it should be a pre-requisite before testing.
 
I don't listen to music after waiting one hour.

You're missing the point. All equipment should be tested at typical stabilized operating temperature.

With many of these PCBs in a sealed box, spot temperatures will elevate, sometimes enough to cause issues.
 
What's the hw version of the one amir measured?
Also can we have a teardown comparison?
 
CR3.jpg
 
The sinad is getting better as the unit warms up so it appears there's a difference beyond test temperature.
 
Well, I thing it is unfair to accuse SMSL before providing strong evidence and let explain their point of view.

So it's necessary to cool down and maybe change the wordings.

I am very interested by the results, but I do not want conclude before having all the elements in hand.


So I used the word "Probably "

And I also ordered another unit. I also hope this is just a "bad unit" and not a manufacturer's credibility issue.
 
Now I have to go to bed for a while ... here is 5 AM ...

Let the recorder continue ... I'll post the results after a few hours
It's 8:10am here in Sydney. I just woke up...
 
What's the hw version of the one amir measured?
Also can we have a teardown comparison?

It would be good for us to know in the test. But would be disaterous if manufacturers were outputting hardware revisions with no indication.
 
This is a unit from my friend ... I must get permission to teardown

Why do people say "teardown"? It's such a brutal word and suggests irreversible damage, stripped screws and broken chit.

Carefully dismantle would be an easier sell to your friend. :)
 
Ok, after 2 hours of soak time, this is what I got:

SMSL M500 Warm-up THD+N.png


We have a degradation of 5 to 6 dB depending on channel. Note that the above is highly zoomed in covering only 10 dB of range.

I then re-rand the FFT in the dashboard:

SMSL M500 L7 vs Amir FFT.png


We have very good matching of the distortion order/level. Second and third harmonic are right on the money.

The noise level is lower in mine but that is affected by FFT parameters.

Looking at dashboard sinad, I see:
1575756735998.png


This is versus 110 in L7's tests. This is within what I consider acceptable given different analyzers, units, etc.

In summary, large amount of difference is due to thermal conditions, not any hand selection of a unit/components.
 
Ok, after 2 hours of soak time, this is what I got:

View attachment 41689

We have a degradation of 5 to 6 dB depending on channel. Note that the above is highly zoomed in covering only 10 dB of range.

I then re-rand the FFT in the dashboard:

View attachment 41690

We have very good matching of the distortion order/level. Second and third harmonic are right on the money.

The noise level is lower in mine but that is affected by FFT parameters.

Looking at dashboard sinad, I see:
View attachment 41691

This is versus 110 in L7's tests. This is within what I consider acceptable given different analyzers, units, etc.

In summary, large amount of difference is due to thermal conditions, not any hand selection of a unit/components.
IMD hump?
 
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