I replaced my Warwick Rockbass (Corvette SE) pick-ups with SD Hot Jazz pick-ups (sjb-2n and sjb-2b). The MEC active electronics are still in place. It's almost working perfectly. Lots of bass, great sound. The only trouble: I can't mix almost no treble in the sound. Is this the way it's supposed to be, or is the potmeter not functioning right.