Buzzing, Humming Through Amped Speakers

[champaul06gti]

hi guys wonder if you can help me, installed in my car is a vibe sub and mono block amp and up until thursday last week was a 2 channel amp powering 6*9 in my rear shelf,

N e way i started to get a loud humming / bussing noise though the speaker when the vehicle is running.

i have tried a different ground, different phono leads, and remote wire, also have tried a ground loop isolation box, but nothing has changed.

N e help or suggestion you can give will be greatly appreciated.

thanks
Paul

 

[Damo-Sri]

1.Is your power cable running down the same side as your phono leads?

2.If you plugged your phono leads in to your headunit whilst the amp was powered and not earthed, some units can earth through the phono leads and blow a resistor in the unit that acts as a ground loop isolator?