Ok - for most folks this is going to fit into the “blindingly bl**dy obvious” category.
Turns out electrical things need current.
I’m using a TinkerBoard SBC and a ProJect S2 digital. The tinkerboard needs about 2A, and I am powering the S2 via USB… part of the appeal was fewer cables as the TB+S2 is now my “on the road” rig. I had a 5V 2A power supply for the TB. It works. But then @Magnus put me on to iFi for power and I have a 5V 2.5A iPower on order. I also ordered their iPurifier2 which I got today. Plug it in and wait for the magic… choppy audio, roon giving the erroneous message of “This track is not currently available from Tidal” or something to that effect… Reboot the core (I’m using Wifi at the moment)… same thing.
I didn’t expect nothing for nothing - the iPurifier was going to have power needs, even though it is plugged in to the USB. It was just enough to push my setup over the limit. Whereas with the RPi when I plugged in the S2 (no iPurifier) with the 2A supply there was nothing… the USB couldn’t power the S2, with the TB it seemed to be working fine. I was getting a lot of lost packets on the Wifi (thanks Netdata) and figured it was the TB wifi module that was poor.
Today I plugged in a 5V 3A supply to the TB. The TB, iPurifier and S2 are now working as expected. With the folks on this forum using SBC + DAC HAT or SBC+USB DAC and other configs - turns out everything needs current (who’d have thunk) and things seem to work that aren’t quite. I’ve noticed this often as Roon losing connectivity to the zone and see quite a few @support cases here where folks with SBCs are complaining about dropout. Make sure your power supply is up to the job of powering everything in your chain. It may not be roon (or Tidal) - that’s just the most obvious visual cue that something is amiss (my stay in hospital isn’t giving me superpowers like being able to see current).