[PROBLEM] Popping sound during playback

[Tim Curtis]

So after testing with another USB DAC I'm not having intermittent popping issues. The only difference I can think of is the previous USB DAC is UAC2 (Amanero), which is also being powered by the Pi. With this other DAC it's UAC1 and USB is being powered by separate 5v supply. UAC2 fix didn't seem to fix pops with first DAC. Hrmmmm.

Linux and UAC2 audio interfaces continue to be a challenge. These same audio distortions were present when I began working with Linux audio way back in 2013. There is no magic fix.

Have a look at some of the Linux kernel USB audio quirks
https://github.com/raspberrypi/linux/blo...b/quirks.c
https://github.com/raspberrypi/linux/blo...ks-table.h

To quote the maintainer,  Takashi Iwai,

"* In a perfect world, this file would be empty." 

-Tim