So I think I know what you're trying to achieve, but I think you're alittle off on its implementation.
Most important thing to realize is your ESP has an Active pre-amp. This is the 3 band EQ. In a passive instrument, your pickups wire directly to passive volume/tone pots (knob), and then go to the output. Theres no battery powering the system, the volume and tone pots work using the signal coming directly from pickup.
In your bass, the pickup signal flows into the active battery-powered preamp, giving you bass/mid/treb controls. Then from the active preamp it goes to the output jack.
If all you want is coil switching (to switch from dual-coil humbucker to single coil) you'd have to have a humbucker with split leads for each coil...the pickup would have 4 wires coming out of it, 2 hots and 2 grounds. Your pickup currently probably only has the hot and the ground, as its set up to always be a humbucker.
You could, theoretically, add a switch between your pickup and your preamp that would enable going from dual coil to single. But you'd need to understand how the switch is wired up, and also where the hot input goes into the preamp. Then you could split the coils at the switch, and send the hot signal to the pre and have it work as it does. I've seen some stock preamps that are really hard to work with or modify, personally I don't do it. You may be able to look inside your bass and identify where the hot lead plugs into the preamp, and then wire the hot lead out of your switch into that. But it may not be so simple, as I am not familiar with ESP active preamps.
Now the whole reason I chimed in here: I've converted 2 active basses to passive before. It involved changing the pickups to better passive-only pickups, pulling out the preamp, and wiring in volume and tone controls. If you want to go that route, PM me and I'll help you. I did this and used a push/pull pot for the volume, and used the push/pull for coil switching to go between parallel and series. But I can't offer much advice to what you're trying to do now, as you'd have to A.) get a dual-coil humbucker with separate leads and B.) get a switch, either 3-pos or 5-pos, and figure out how you can mount it to your bass, then C.) figure out the individual coil wiring, solder all the pickup leads to your switch, and send the hot signal from your switch to wherever you disconnected the pickup from the preamp.
Theres no telling what this experiment will sound like, but from what I've seen, making a humbucker work as only a single coil usually drops alot of volume and bass output, and adds alot of single coil hiss. Ie. its not useable at all. But to each his own. Theres alot of possibilities open to you, but for what its worth, I spent months modifying a bass to "get as much versatility out of it" as possible... I made an active Jazz bass passive, added options for series or parallel mode, and added a treble cap on the bridge pickup to get the Rickenbacker-style option, and after it was all done, the best tone was just both pickups full on with no bells and whistles. Was a fun project though.
Whew that was a mouthful!
Originally Posted by Road Bull
Is it satan worshiping doom? Then I am not interested.
Last edited by Toastfuzz : 12-17-2012 at 11:44 AM.