i put a pioneer headunit that a friend of mine gave me into my 4th gen, i still have the bose amp and speakers, everything works but for some reason at low volumes i hear a humming comming from the speakers. it happens when i have either a CD or radio on. i asked my friend if maybe he had a problem with it before and he said no, but that it could be a grounding issue. is it the bose amp? the only thing i can think of is maybe its just a feedback or something from running the amp on the headunit and the bose amp. just wondering if any of you audio-philes had this before. thank you guys so much for your time

 

Headunit preouts are shot, most likely.

What pioneer HU is it?

 

its a panasonic, (dont know why i thought it was a pioneer)

CQ-DF802U

i used the harness you have to splice with. you think maybe using the RCA outputs would help?