The Ibanez factory wiring somehow utilizes the active treble control as a passive tone knob when the bass is set to passive mode. I've seen some wiring diagrams for the OBP-3 and have only encountered diagrams where the passive tone knob is a separate knob. Has anyone had experience wiring a single knob for two purposes like this? Edit: If it helps, The bass has 5 knobs, two switches. Active bass, mid, & treble. Passive/active switch, 3 freq mid eq (switching to 2 band with OBP), 1 volume, and pickup blend.