So I am on my second power mac and am having the same problems when it comes to hooking it up to my home stereo. When everything is hooked up I can hear voices in the background whether or not anything is playing. When I shut the computer off it's still there. However when I unplug the cable from the computer it vanishes.I think its a radio show im hearing by the way. I can't figure this out for the life of me. My first mac (B&W G3) did this and now my current computer is too (DA G4). How do I fix this?