S3 Audio Problem With Aftermarket Stereo

[hugepiece]

I've just purchased a 1999 Audi S3 with the Bose option but no headunit attached. It already had the correct Bose converters fitted to allow me to use RCAs. I've just fitted a Kenwood mask unit. I'm using both RCA outputs for sound and not the speaker outputs at all. All is working except for 2 problems - Firstly i get a soft whine over the audio that gets louder as you accellerate but not to the point that you cannot hear properly. Secondly and probably worse, I get a loud popping noise from the speakers whenever I change sources or change radio channels etc. I've checked the loom and everything seems ok. Would appreciate any suggestions as this is driving me mad. Thanks.

[hugepiece]

incase anyone is interested, I installd some Ground Loop Supressors/Isolators today and problem is solved!