I've two problems with my new Mac Pro. The one that's discussed here: http://forums.macrumors.com/showthread.php?t=1017977 and an intermittent "plopping" sound through my Line-Out even when the line-out is muted (e.g. while playing a game with headphones). It sounds like connecting and disconnecting an audio cable. I've connected my amp via a klinke cable to the line-out of my Mac Pro. Any hints for a solution?