Mac G4 Power Book 2006 and/or Mac Mini Intel 2006


What’s everyone using for computer file music playback?

Software? What can playback DSD?

Hardware?

Power supplies?

I have an old Mac G4 Power Book and a couple 2006 Intel Mac Minis at my disposal.  Any thoughts on software, hardware and what outputs work best on those Macs? I will be sending signals to both an Oppo 105D and a Music Hall DAC 25.3.

Just looking for some reasonable 1st steps to creating solid file-based music playback that can accommodate hi-rez files as well. 
128x128brettmcee