Need Help With Humming Noise After Installing Stereo

[nsta]

I recenetly installed a new sound system into my r33 and have got an issue:

basically the headunit has 2x preouts, and ive run two sets of rca leads from my headunit to the amp in the boot, , now if i plug in only one set of rca leads into either the headunit or the amp, the static noise is fine, and everything is ok. But if i plug in both sets of pre outs, the static noise is much more apparent, and once the car is turned on, this little hum turns into a loud high pitch noise coming from the tweeters from my splits......

what could this problem be?, im getting really frustrated, im thinking either:

a)crossover to tweeters, as its really only the tweeters making the noise (from both splits)

2)need better rca cables, more shielded ones?

also, this sounds gets louder the more i rev the car.....alternotaor whine?

Edited November 17, 2007 by nsta

[nissanskyrice]

had the same problem with mine. sounds like a ground loop problem - headunit and amp are grounded in different parts of the car. you could either run the ground lead from the headunit thru to the amps grounding point or buy some ground loop isolators (much easier option). they plug inline between the rca's and the headunit and cancel out the ground loop. worked a treat on my car. you'll need one for each rca lead and they're usually around $30 each. most car audio places will stock them. i still get a little noise thru my fronts but its only noticable when the volume is turned right down (so not very often)