pre-out noise

ok, the rear preout on my head unit is making a buzzing noise, i thought it may be from some kinda of rca misplacement too close to the power cable or something, but when they are connected to the front preout, the noise isnt present.  im not dumb when it comes to this stuff and i tried everything i could think of.  im puttin in a 4ch amp and need some answers on how to fix this problem.  thanks

Have you try with a High quality RCA?

yeah i use fosgates, its not a problem with the wiring to the amps, its somethin with the cd player wiring cuz i used the same wire to test them and the rear set made the noise