I first posted this in the ICE section but I guess they don't get so much traffic through that neck of the woods. The other week I fit an AUX cable to my audi concert head unit by basically tricking it into thinking it was the CD player. It works fine but I get an interference when listening through the AUX, I'm guessing from the alternator as is goes up and down with the revs. Some one said I need to fit a capacitor or something. . . Can anyone shed a bit more light on this for me please or have any other ways of combating this interference? Also worth mentioning it's not the device as I get this interference even when nothing is plugged in but CD (AUX) is selected Thanks!