Actually, I would agree with the wrapping of the RCA's to a ground. When you are doing a high volume of FM modulators (dealership headrest TV's, etc.), amp installs, etc, this is a great known "down n dirty" method to isolate the issues and quickly. I have seen many vehicles that had all brand new gear installed, good equipment with power and RCA's run opposite sides of the vehicle, still getting the whine. Even gone as far as running a temp. jumper for amp ground to the same factory radio wire ground on the vehicle still to get a whine. Sometimes it just cannot be contained even when completely and professionally wired. We try to only use ground loop isolators as a last resort because as aforementioned, they are only about 50% successful.

That being mentioned, ALWAYS start with the basics- good equipment, good wiring, sanded and tight amp grounds, RCA's run completely opposite side of vehicle from power cabling and kept completely seperated, etc. If all else fails, ground the RCA's (I would wrap the raw wire as in the pics but we have found that it is more successful sending the other end of the wire NOT to the radio chassis but to the factory ground wire going into the factory radio harness).

Do it for a living managing multiple installs per day (all done professionally and properly), and you are bound to run into this a few times! Ask any professional installer. The difference is the installers who can actually fix it. We probably get at least one of these jobs a week where someone has ripped their hair out going over wiring, installing isolators, etc just to find that this method ends up being the only one that works!