I have got a 580W Pioneer amp fixed to the rear of the back seats in my Focus ST170. Its started playing up and i am getting alternator noise through my speakers, sounds like a supercharger. I have been told its a bad earth, so i rubbed a section of paint away and took it to bare matel under where the seat belt bolts and fixed the earth here. It was ok to start with but its gone back to producing alternator noise again after 6 months!! Checked all connections and everything seems ok.
The only thing it might be is where the power and earth connectors are soldered to the amp wiring board, it seems a bit loose there. Would this cause it? or is it nothing to do with the amp side of things. Im trying to establish the cause. It only does it when the amp is on
Thanks