Audiolab Q-DAC

I don't know what can be measured in the DAC, using the ADC on the WM8782.
Even by difference methods.
It can be used for nothing more than tube amplifiers...

, just swipe xtal on XMOS

I designed many different USB audio interfaces, using NXP CPU and 2 families of the XMOS CPU.
All these interfaces have external audio clock and galvanic isolation between USB and audio part.
And I have never faced with the influence of CPU clock to the audio quality.


Alex.
 
I've faced with audio quality through USB just with two different motherboards. I'm tired of proving the obvious to people. To users with XMOS USB interfaces - try it, it is very simple and inexpencive. More precisely, it seems completely stupid to have to prove to skeptics and owners or creators of very good expensive devices the difference from a cheap upgrade for another peoples benefit.
 
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I'm tired of proving the obvious to people.
You haven't proved anything. What you have shown is misuse of DeltaWave. If you show a greater than expected difference of two short recordings how can anybody tell which is better and what is causing the difference. Only thing it proves is that either there is something wrong in your measuring setup or both recordings are bad.

Should not be too difficult for you to try to prove your point:
  • Make two 60s recordings of a music track you use for listening tests.
  • Post both recordings and the original.
 
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Reactions: altor
Just a hint: this thread was about repair of the Q-DAC but the DAC Meisters again **** up a thread. Some are very keen pointing others at being off topic but this thread probably will again derail to the usual off topic pointless drivel. Please request a separate subsection where you can have contests who is right and who is wrong as it is NOT in the interest of readers.
 
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Should not be too difficult for you to try to prove your point:
At now it is impossible, this SMSL upgraded already and I threw out 24MHz xtal, when I get my hands on another device with XMOS I'll do it for you (next time will post with WAV file no copyrighted free music). I have these two recordings in a 1 minute duration. I cant share it because of copyright. I can compare it with original, but need to search it on Youtube (yes, I recorded this not familiar track for me, just a suggestion youtube on main page). It is just from Youtube difference, can you imagine. Both files are adjusted and fit perfectly, I can work with audio editors and familiar to Cool Edit, Sound Forge and so on from early 00 years.
what can be measured in the DAC, using the ADC on the WM8782.
It is simple audible thing between stereo channels in phase characteristics, I don't need to measure even 0.01 difference in THD.
 
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Both files are adjusted and fit perfectly
If you only change the XMOS clock there should not be any need to adjust anything. And it is better to leave the matching to DeltaWave. If there is a real phase difference it should be visible no matter where the track comes from. XMOS clock allegedly causing the difference does not know anything about the track quality.