Ok 1 month ago i took out my RF HU and replaced it with the Pioneer 9650 (dual face one) and now i get a buzzing noise in my speakers and is louder when i put the foot down on accel. Was just wondering if it could be because the unit uses alot more power it needs better power and/or ground? As nothing was moved other than the HU swap and i no get the buz. Done it in my dads car aswell. Both are Ford EB's.Any suggestions?Cheers

Could be the fuseable link in the pioneer

or have you tried moving the RCA's? maybe they are near a power cable

The fuse that is on the 12v line going to the HU?

fuseable link is located in the headunit, which is common in pioneer headunits, but may not be the cause

Id put money on it being the ground. Try finding a better chassis ground rather than using factory and buzz should hopefully be gone
peace
Cyberpunky

agreed try upgrading your ground fisrt, but you may have blown the fuse on the rca tracks inside the HU, ~$80 fix from pioneer.

Yeh it was like that since new and the ground wire is thin. I will try ground first hopefully that is it . Would it be fine to run the Power and ground straight to the batt aslong as it is fused?

yes most definitley, but it is not really needed, if you do fuse close to the battery to protect the wire