I've just had EMG's installed on my SR 1300 and they don't wire up to the stock preamp. I need a preamp that I can use the midsweep/contour knob on my bass. It's wired now to have two volume and tone controls for each pickup and I hate it. I wish I could get the OBP-3, but it only had a mid toggle switch. It's not sweepable.. What are my options here? I have vol, bass, treb, mid sweep/contour, pup pan. I need a preamp I can use all these pots with! Also, if there is any 18V conversion kits I can install in the process, that'd be a plus. Thank you kindly for all your ideas.