Contour Enthusiasts Group Archives Forums Modifications Audio loud pulsating thumping noise from amp

my friend amp makes this loud pulsating thumping noise when its on ,it dose it when the engine is on and off, but when you un plug the RCAs it stops ,does any one know what may cause this. thanks

Have you tried a new set of interconnects?

My sub had an intermittent thump, thump, thump that turned out to be interference from my Motorola cell phone. Sounds dumb, but as soon as I turned it off, the problem cleared up.
Likely not your problem but shows how small a gremlin can be.
Cheers

you should check your ground wire. also something is possibly crossed or tangled in the rca line or speaker wire somewhere. make sure all your wires are shielded.

well its either your ground wire or your internal ground on the amp is shot....but its the ground....check that out ...