More ground problems!

I have  a pioneer premier 6700 headunit. problem is when the antena is plugged in u can unplug the ground and hu still plays,but sub outputs have terrible noise, turn on /off thump.but the rear rca outputs are krystal clear.i am pretty sure problem is in head unit.but any suggestions for testing i could do would help.rottenbellys 05 crew cab colorado.Pioneer dehp 880prs, kenwood excelon in all 4 doors. Bazooka 500 mono Jl 10w3 in coustom center console box.

The problem is indeed in the head unit. The outer shield of an antenna and the outer shield of an rca cable both are connected to ground at the other end of the cables which is why the deck will still work. It is not adviseable to operate your cd player in this fashion. Pioneer head units IMO, have a piss poor circuit design as it relates to ground. Time to take it to the service shop dude.Top Secret, I can tell you but then my wife will kill me.