I also use the Griffin iMic to hook my Cube up to my home stereo system. But I also had to get a ground-loop isolator cable because the sound signal had a ground-loop hum. The isolator (in the U.S. it's a $15 cable obtainable at any electronics store) fixed the problem.
I use an Apple AV cable to connect from the iMic to the isolator.
[ 11-28-2001: Message edited by: Michael T. Doyle ]