piCorePlayer - crackling with RpiZero USB audio

Hi,

Thanks for the awesome work with piCorePlayer. I've been using it for a while, but recently switched from HDMI out (to a receiver) to the Aune T1 SE MK3 USB DAC headphone amp and I'm getting a crackling/popping sound. It's only occasional when listening to CD FLAC sources, but constant with DSD files (FLAC and DSF).

I've tested a few combinations:

• Pi Zero using USB - noticeable crackling
• Pi Zero using HDMI out - no problem (although I can't test higher bit rates with that setup)
• Pi 3 using USB - no problem!

The Pi 3 testing is using the same SD card, and therefore the exact same settings, including the in-built wifi for networking, as the pi zero.

I've played with all the options under "USB Audio tweaks" without success.

Any idea why the pi zero has a problem, but not the pi 3? Obviously the CPU is significantly less powerful, but even on the zero the CPU is 50% idle during DSD playback.

Thanks a lot.