I'm streaming Spotify/iTunes to UD-301 to Sunfire Symphonic Reference Amp to B&W 804 Matrix. Love the sound.
Also have a spare UD 501 sitting around that I don't use because I prefer the use of a volume control knob thats on 301 but not 501.
Also have a spare UD 501 sitting around that I don't use because I prefer the use of a volume control knob thats on 301 but not 501.