I'm not familiar with the DRM-600. How does it output its analog audio
stream, RCA jacks? Does it have a headphone output jack? If so, do you
get audio through the headphones when you play the CD using Music Box? Do
you have the audio output from the changer plugged into the PAS' input
jack? It should be no problem getting audio into the PAS and so MMWin can
manipulate it if the DRM-600 has audio output capabilities. More hardware
info specifics are needed to diagnose the problem.