I own the Rotel ra-12 am the best way to connect is via the optic from computer to amp, I have two desktops one with M-audio 2496 card connect via RCA and the other Pc has optic connect. played the same track simultaneously the optic was more pleasant to listen and in my opinion it sounded better. your computer inuputs the file so yes acc, flack mp3 wave whatever will be processed by amp. you cannot connect the amp to computer via USB, USB is for only media device I have used iphone ipod touch and Moto G phone via bluetooth. thinking pretty much any stream-able device via bluetooth and only Apple products via USB port hope this helps
