I have a passive bass with 2 soapbar pickups. There are 2 independent volume knobs and 2 independent tone knobs for each pickup. Is there a way to maybe rewire the bass with a master volume, blend pot and possibly bass and treble....basically using all four knobs but trying to get more tonal variety. Anyone out there know if this could be done? Do you have or know where I can get these schematics? Just curious. Thanks!!!!