I had to notice that my Digi+ (transformer version) stops sending a signal to my amplifier on smallest fluctuations of current/voltage:
When I switch on/off the light in the same room, or plug an electric device (e.g. a radio) into the wall-socket, or switch on an electric device (e.g. toaster), the sound stops.
The Raspberry continues to play (audible via the headphoe-jack).
When I stop & start the music, it starts again via Digi+.
This happens on both output, electrical and optical.
I tried the same with an usd-soundcard with toslink-output, which worked flawless without any problem.
I hope there is a solution for my problem, otherwise the digi+ is useless for me.
Digi+ mutes on minimal fluctuations of current