Audio Systems: Car audio, ground loop isolator, vp commodore

Question
Tom,
i have a VP commodore which i have recently upgraded the sound system in, when i first did this and had the amps just sitting in the boot there was no sound interefernce however now that i have secured them i have the enigine noise and interference coming through the sub. the strange thing is it doesn't come through the speakers or anything when i connect them just to the headunit only when they run through the amps. the amps are mounted on boards and not touching the car body at all, and i have tried numerous earths for the amps why might this be happening? also the power and speaker wires are running down seperate sides of the car?

Answer
Jason,
The problem may be that you have a ground loop fault. In most cases, if possible the amps should be mounted as close as possible to the head unit. if you mount the amp/s in the rear/trunk you may need a seperate battery that only powers the amp and you must use a ground loop isolator. The power wire for 12 volts should be as large as the hole that the wire connects to in the amp. The ground wire should also be the same size and it must be kept as short as possible and securly connected directly to the cars body/frame. The wires for the audio input to the amps should be monster cables that are double shielded to help stop noise pick up. I have found that on some sound systems the noise can also be toned down a bit by looping the power and input lines through seperate torrad cores from radio Shack.

TOM,
T&D ELECTRONICS