hi! here is the problem: my 75 ri jazz has 9J pickups, and an emg BTC pre (bass/treble). saddly, my bass sound fells like I'm slapping all the time, high dynamics but poor fundamentals, aggressive mids... I asked a luthier, and he tolds me that the "problem" could be explained by a unfunctionnal working system 9j/BTC, and it was best to put a bartolini pre into the bass, to work with the 9J's. any advices? did anyone meet that kind of problem?