I've rewired my J-bass according to the P-bass diagram from Seymour Duncan. Works great. An anomaly is the tone pot though. It works the wrong way now. Turned up all the way the pot removes the highs. If I turn it down the sound becomes clearer but a slight hum is introduced. Why could that be? Regarding the wiring: Everything is P-bass with the middle pot not in use and bridge hot and neck ground are soldered together.