A new question, in addition to the above: I’ve been looking at the wikipage on „power as a source of error“. It says the requirement for
Raspberry Pi 2 / 3 and HiFiBerry AMP+ is 6A / 12V
I have the MEANWELL GS60A18-P1J that is sold by HiFiBerry for the AMP+ but its specs are 3.33 A / 18 V (60W max). Is this a possible problem? Too few amps? I know that the R-Pi on its own requires 5 V / 2.5 A and if one uses one with less amps, there are problems.