I have a Jazz bass that I've converted into a V/T V/T concentric knob configuration with a series/parallel switch. When I have in parallel, it's just so quiet to the point where I need a significant booster just to be heard. It's gotten a lot worse since I installed the Super 55 pickups, which have a three wire configuration. When it's in series, it's really loud, though. What gives, and how can I fix it?