Running Plexamp v2.0 Beta 2 on Raspberry Pi 3 with HiFiBerry Digi+ Pro. I love it – it’s fab BUT:
On audio close to full scale there is noticeable distortion/clipping. The same audio file, played on the same system through the Plex web app, doesn’t distort.
I have tried with and without audio normalisation.
It’s not a generic Plexamp problem – playing the audio through Plexamp on a Mac is fine.
Not with Plexamp, but with LibreElec (and thus PMP embedded) I have found that I have to reduce the volume on the RPi by -1.3dB, or it will distort.
Most likely to happen if you go per HDMI to a TV from Sony and then from there per TOSlink to an amp.