Username is vehicle in question with a /6, Ive done radio swaps, swapped alternators, grounded the radio, grounded everything else, even installed a noise suppressor on the Alt. Power line and then swapped it to the radio power line and I still get interference that varys with engine speed. If I disconnect the Alt power line the noise stops, What can be causing this and what do I do to make it stop? Im at my wits end with it!!!

slants down here had a noise supressor instaled along with the volt limiter on the back of the dash. If you ain't have that one installed, you won't be likely to get rid of that noise... I KNOW why i'm telling you so