Hello,
I am lucky to own a Abacus Preamp-14 with integrated streaming device AroioEX, based on RPi. It came with Abacus’s own Linux-based OS named Aroio, where integrating streaming services is everything but a charm. For months I struggled with Spotify. Sometimes it worked, mostly it did not.
So I disassembled the Preamp (I just removed some screws), removed the SD card, installed Volumio on the same card, inserted it back again - and it ran out of the box. Only, the DAC is recognized as a HifiBerry DAC Plus. But I am not sure, if that matters at all. Maybe, some of the original features are missing (Aroio integrates AudioVero, which it did not try and Abacus claims to get the very best out of the DAC). But for me, Spotify worked as expected for the first time, since I used the Preamp 14.
Coming to sound quality: I additionally signed up for Qobuz. And now, the sound is just amazing!