I have a Raspberry Pi (with a IQAUdio sound card) that is running Plex Media Server.
The same Pi is also running PlexAmp.
The scenario is this is all housed in a single box, along with main amps, sits there chugging away all day. Using my phone, tablet, PC I can pull up a Plex client, choose to redirect to the PlexAmp, choose a piece of music and away it goes.
I was under the impression that the playback would be in the original quality, namely the CD quality 16 bit/44.1 KHz FLACs that I wripped the CDs in.
The server will send the file as it is to plexamp, as long as it is found to be situated in the local network. So a flac in full CD quality will arrive as such on the Pi.
The exact sample rate is determined by whatever is set as default for this sound interface. What exactly gets selected you can see in the plexamp log file. It will usually be 44.1 kHz, but might be also 48 kHz on some systems.
Every file with deviating sample rate will be resampled (on the Pi).