[PROBLEM] Popping sound during playback

[leicray]

I have been running 6.4.0 for a while on an RP2+ without any problems. Audio is output via USB into an Audiolab M-DAC.

I recently purchased an RP4+ which exhibits the popping noise about which others have complained. This new Pi also runs 6.4.0 configured in the same way as the RP2+ and connected to the Audiolab M-DAC in the same way.

As far as I can see, everything is identical apart from the Pi on which moOde is running. Any ideas about why the new set-up causes popping?

Thanks.