each amp controls something different. The deck has no power output of it's own, it runs off the amps. If you can figure out which amp controls the bass then you can just replace that amp. You can find them on ebay fairly cheap. I can tell you that the front amp under the cd deck controls the front tweeters on the door pods. Mine went out so i replaced the deck but have regretted it since. The sound quality is just not the same as the mach system. I wish i had found out about the system and just replaced the defective amp instead of the head unit.