I bought an EMG MMCS pickup for a Musicman SUB bass. The internal preamp is set flat. I want treble and bass pots, but I don't want to spend another $100+ on their preamp controls. Is there a wiring diagram to solder up regular pots? I have a 5 string ESP bass that this tech soldered the EMG's up to the stock pots, so I know it's possible. Thanks in advance!