Did some searching, can’t find any solutions to this. Just bought a new bass with an active/passive switch. (‘96 Ibanez TR500. Freakin rules!) I have a newer Soundgear bass like it where the treble knob acts as a tone knob when in passive mode. The ‘96 bass doesn’t have that. I’d like to make that happen without installing a new preamp if possible. I have no idea where to start. Anybody have any insight? Where should I look for a wiring diagram I could send to my luthier? Thanks!