What we had to do was fit an earth loop isolator (ie. RCA line transformer) in the inputs to the front amp. I think the fact we had to, and the major noise problems we've experienced with Paul's TT on both occasions are more to do with the car itself, rather than the Empeg as such. A lot of the problem stems from the fact that the car comes with a semi-active system already, which can't be easily bypassed without fairly major time and cost. The original amplifiers on the rear speakers sit at a different ground potential to the rest of the system, inducing major earth loop problems. In an ideal world, the best solution would probably be to completely replace the rear speaker system, but I think there's probably a good chance interference would still be an issue - the TT seems to be an inherently noisy car electrically - in much the same way as late model BMWs also seem to be.

Dominic

Cambridge Car Audio
http://www.cambscaraudio.co.uk