I have changed strings, cleaned the battery contacts, I even got behind the contacts, and pushed them up a little to make better contact with the battery. Whats happing is everything seems OK then the sound gets thin like there is no Bass tone I have to turn up the bass knob all they way up to get any bass tone and even that doesn't give me that Ballsy tone that Music Man gives, I'm thinking it is the pick up or could it be the Preamp? PS It dozen,t do it all the time you,ll be playing everything is fine then all of a sudden it sounds if someone walked up and turned the Bass knob all the way off. Thanks.