Some thumb rules:
1) You don't need fancy specs for a dedicated music PC
2) Fan noise is your biggest enemy. Get the quietest SMPS and the quietest processor your biudget allows
3) Analog out from soundcards are underrated. They're often very good sounding.
4) If your soundcard and DAC allows, AES/EBU is the interface to use. Even electircal S/PDIF is very good.
1) You don't need fancy specs for a dedicated music PC
2) Fan noise is your biggest enemy. Get the quietest SMPS and the quietest processor your biudget allows
3) Analog out from soundcards are underrated. They're often very good sounding.
4) If your soundcard and DAC allows, AES/EBU is the interface to use. Even electircal S/PDIF is very good.