Totally, that\'s what I presume too. Higher-pitched noise that occurs that starts while on / pre-ignition. That\'s what led me to believe the aftermarket TV installation "birds nest" was the culprit, rather than potentially the alternator (am I wrong about this?). Noise does increase with revs however, so I might be chasing two sources for all I know.
I\'ll go the ground loop isolator if I need to. I\'d prefer to do this cleanly and properly and possibly negate the bit of sound quality loss through using an isolator.
While I was doing a bit of reading on this before I started attacking the car, some people have pointing out that ferrite cores (usually come with TVs and the like) have sometimes been shown to reduce noise to a similar level of a ground-loop isolator. Could be BS, but they presumably exist for a reason..
Edit: Bleh.. it ended up being the secondary cig lighter socket I wired up. Serves me right for using something that was pretty poor quality. This project has made me feel like an idiot every step of the way. At least I\'ve learnt a lot..