To add to this, there's even the capacity to add usb dacs if the underlying distribution supports it. Picoreplayer was my introduction to these tools and I'm pretty sure it's my final destination. Can't recommend it enough if they have the time and curiosity to get it set up.
I would also add that if the person OP is asking on behalf of is not so inclined to get into the technical parts and okay with possibly throwing money at the project, volumio is there. I tried this first and appreciated it for what it was, but I wanted features behind the pay wall which are readily available for free with pCP.