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

Feyire

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Ok, after 2 hours of soak time, this is what I got:
Given that we have devices that improve in measured performance when warmed up over time and others that degrade, I'd really like to see this type of SINAD over time measurement became standard here at ASR.
 

PierreV

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Given that we have devices that improve in measured performance when warmed up over time and others that degrade, I'd really like to see this type of SINAD over time measurement became standard here at ASR.

Do we have DACs improving as they warm up? I am not well informed in the details of their low level physical implementations, but in other sensors (imaging) an increase in temperature always means an increase in dark current and ADC noise.
 

Feyire

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amirm

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IMD hump?
It shows up but not as extreme as it does elsewhere:
SMSL M500 DAC and Headphone Amplifier IMD Warm up Audio Measurements.png
 

Feyire

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@amirm, so the hump is not present when cold, but appears when warm? If so, that opens up Pandora's box on the IMD hump issue once again... and puts into question whether previously measured devices without the hump only did so because they were cold/colder. For example, you would need to revisit ESS DACs, but also AKM DACs again.

This will continue to be a very interesting issue to investigateo_O
 

JohnYang1997

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How tf??? Thanks for measuring. I was thinking like, perhaps we get to know what component that changed performance. Turns out it's unknown again.... What about other dacs that didn't have imd hump shown? :oops:
 
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amirm

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Given that we have devices that improve in measured performance when warmed up over time and others that degrade, I'd really like to see this type of SINAD over time measurement became standard here at ASR.
I have run this with amplifiers. Here is an example of Hypex NC400:

Hypex NC400 Amplifier One Channel Driven Warm Up Distortion Measurements.png


I don't think it pays to worry about such things. I divide the DAC SINAD into just four buckets for this reason. A few dBs here and there don't mean anything in practice.
 

amirm

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How tf??? Thanks for measuring. I was thinking like, perhaps we get to know what component that changed performance. Turns out it's unknown again.... What about other dacs that doesn't have imd hump shown? :oops:
You guys are determined to glue me to my desk the entire weekend performing these tests. :)

I just packed everything I had into the attic to clean up my overflowing lab. So digging up old products takes a lot of effort and pain (can't stand up in the attic). I will see if I can find another instance to test.
 

Feyire

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You guys are determined to glue me to my desk the entire weekend performing these tests. :)

I just packed everything I had into the attic to clean up my overflowing lab. So digging up old products takes a lot of effort and pain (can't stand up in the attic). I will see if I can find another instance to test.

You said that Topping claimed they definitively fixed the hump issue on the D50S, which you confirmed with a measurement.

It would be really interesting to see a new set of measurements on that device with the SINAD over time chart as well as including IMD measurements over time to see if the hump re-appears at a later stage or not.
 

Feyire

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1575759174978.png
 

ninetylol

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Being a silent reader on these forums for a few months now and just had to create an account so i can say i was here when this thriller happened :D

Also thank you for all the work and your measurements!
 

MusicNBeer

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Well my m500 has been on all day and sounds awesome right now, so for all practical purposes, these deviations are moot.

Regardless, thanks for all the efforts. Your work will definitely push the technology forward even further.
 

restorer-john

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Whatever way you look at it, all testing going forward needs to be at stabilized operating temperature after an hour (graphs seem to show that would be sufficient).

Manufacturers will scream tests results are not typical of real-world usage otherwise.
 

Koeitje

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What hardware version do you have @amirm?
 
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