04-15-2021, 12:31 PM
(03-07-2020, 03:51 PM)l eicray Wrote: Hi Kent,
Many thanks for the additional suggestions. After lots of test combinations, and rewriting of microSD cards, I conclude that the USB ports on a Pi-4B do not play nicely with some USB DAC-like devices.
I have previously reported that my Pi-4B causes a popping noise when connected to my Audiolab M-DAC, though the M-DAC works just fine when connected to a Pi-2B running exactly the same version of moOde. However, the Pi-4B does work fine with a simple USB audio adapter (Trond AC2-B). The adapter would have been a possible solution, but the volume is simply too low and that's why I bought the Cyrus soundKey which incorporates an amplifier.
I have now tested the soundKey connected to a Pi-2B and a Pi-1B, again running the same version of moOde, without any problems. This suggests that the Pi-4B is the culprit. For some reason it plays nicely with the Trond USB audio adapter, but not the M-DAC or the soundKey
My intended solution is to put the Pi-4B into safe storage for now and buy a second Pi-2B (very reasonably priced on eBay for a new unit) as I know that that will work.
There is at least one report of a kernel bug in Ubuntu causing problems with the 4 GB RAM version of the Pi-4B (as is mine), so perhaps a solution to my problem will arrive in some future kernel update for Raspian. Not holding my breath. however.
Again, many thanks.
