I'm getting the Aguilar OBP-3 onboard preamp. I have a Conklin GT7 that has 4 pots Volume,bass,treble,balance (Correct me If I'm wrong)so the 3 way eq im buying has an extra pot the "Mid" so I'll need a concentric pot with a stacked knob. I suppose aguilar preamps do not come with knobs. so where can I get a concentric pot and a stacked knob like a good looking pot. My bass is the red one and it has black hardware so what would look better black knobs? tell me your suggestions please. and also how much do you think the preamp + concentric pot + 3 normal knobs + stacked knob be? and do I need a switch? thanks a lot for the patience.