alright i bought my first 1991 audi coupe quattro and when my car is off the cd player works fine but when the cars running it whines like a high pitch whine (out of the speakers). a friend said it was the aletnater, but does any one out there have any other idea?

 

check the grounds ... some stereo wires might be gettin' interference

 

that's strange, does it make the sound at idle? or only when you step on it?

this page should help you out http://www.termpro.com/articles/noise.html

 

it does it at idel but you really notice it when you step on it