Fancy Humbucker Wiring??

[duhvoodooman***]

Any of you Fretters have experience with this stuff? I was kicking around the idea of maybe buying a 4-conductor hot bridge pickup like a Duncan JB or Custom for my "new" Dot and wiring it with a DPDT "on-on-on" toggle switch for series-coil split-parallel capability. Would entail drilling a hole in the guitar for the added toggle switch, but that has to be pretty easy with a semi-hollowbody, compared to a solid body. Seems like it would be a cool thing to have those different sounds available. But I wondered if anyone here has done this, and what their experience was? Worth the effort? Pitfalls to avoid? Any hints on working inside a hollowbody? Seems to me that like that might be the trickiest part....

[duhvoodooman***]

C'mon, Fretters, talk to me! Somebody out there must have done this! I just picked up a used Duncan JB on eBay this weekend, so I'm starting down this road....

[Cranium]

Im confused, aren't your pickups already 4-conductor?
(By the way DVM since you are quite skilled with wiring and stuff could you please explain how to wire a 4-conductor wire "stacked humbucker" single coil for single coil operation, Im still a little confused about this.)

[duhvoodooman***]

Im confused, aren't your pickups already 4-conductor?
(By the way DVM since you are quite skilled with wiring and stuff could you please explain how to wire a 4-conductor wire "stacked humbucker" single coil for single coil operation, Im still a little confused about this.)

Re: your question about humbuckers being 4-conductor, the answer is.....yes and no. They are all 4-conductor in the sense that humbuckers have two magnetic coils which obviously each have a positive and negative end. But virtually all stock humbuckers (and many aftermarket ones, too) come with 2-conductor output wiring, because the other two have been internally connected to put the two coils in series. So the two output conductors are the negative end of one coil and the positive end of the other one.

Having all four conductors come out of the pickup gives you the options for the "fancy wiring" I'm referring to above. By using a properly wired double-pole/double-throw (DPDT) switch, you can run the two coils in series (i.e. the "normal" way, which gives the strongest, fattest sound) or parallel (a somewhat thinner, more trebly sound, but still hum-cancelling). With a 3-position DPDT switch--what they call an "on-on-on" configuration--you can also drop out one of the coil signals completely, basically turning a humbucker into a single-pole, with a much brighter but somewhat weaker signal, and no longer hum-cancelling. This is what is commonly referred to as coil-tapping (not really an accurate term for it) or--more properly--coil-cutting.

Unless you want to have all three options of series, parallel and coil-cut, there are much easier ways to add coil-cut capability to a guitar's pickup wiring. It can be done with a "push-pull pot", which is basically just a combination potentiometer and switch in one integrated mechanism. You simply replace one of your guitar's regular pots with a push-pull wired appropriately to the p'up of choice (most commonly the bridge), and you can cut a coil just by lifting up (or pushing down, depending on how it's wired) the pot's knob. This activates the pot's switch, sending one of the two humbucker coil signals directly to ground, rather than to the amp. Also, by using a push-pull pot, you don't have to drill any holes in your guitar (always an unnerving prospect!) and you don't change its appearance.

HERE is a nice, clear schematic for wiring a coil-cut push-pull pot on the Seymour Duncan website. Note that for an SD humbucker, the primary coil ("screw" coil) is wired with white (-) and black (+) and the secondary ("stud" coil) with red (+) and green (-). As shown in the diagram, the two coils will be in the normal series configuration with the switch in the upper position as drawn, and the secondary coil will be cut out with the switch in the down position, since the red wire will then go to ground.

Actually, I'm looking at adding a 3-way DPDT switch for the series/parallel/coil-cut capability on the bridge humbucker and a push-pull pot, which will be wired to allow me to switch the bridge and neck p'ups in and out of phase (a.k.a. the "Peter Green mod"). The out-of-phase mode gives a thinner and rather hollow sounding tone that's quite interesting. I wouldn't want to have the two p'ups set up this way permanently, as Green did by swapping the magnet polarity in his neck p'up, but it's a cool additional tone to have "in the pocket". This "phasing" effect only works while you're playing through both pickups at the same time. HERE is a schematic of this wiring configuration on the Duncan website.

By rewiring the pickups as I'm describing, I'll end up with a total of 10 different pickup combinations vs. the stock 2-humbucker's three. I'm sure they're not all equally useful, but it will be fun to play around and see which I like. If you don't add the phase switch, you still get seven combinations. If you really want to go nuts, you could add a second DPDT switch for the neck humbucker and get a total of 24 combinations, if my math is right! But that seems like total overkill!

EDIT: Here's a full schematic I cut'n'pasted together showing the complete bridge humbucker wiring mod I intend to do on my Dot, including all the contact points on the switches & pots--

Attachment 410

[marnold***]

I have no idea how to help you, DVM, but it sounds like a cool idea.

[Spudman***]

Don't drill holes. Just get push/pull pots for the volumes and do the Jimi Page thing. That way your guitar stays in a more valuable state...and I ain't talkin Connecticut.

[duhvoodooman***]

Don't drill holes. Just get push/pull pots for the volumes and do the Jimi Page thing. That way your guitar stays in a more valuable state....

Interesting idea there, Spuds, but I think I'll pass. Wiring up all those push/pulls together looks like it might go well past the limits of my meager electronics skills! Besides, I'm really not that concerned about adding one more small hole to the top of my Dot, which has plenty of them already! If it was a $2,000+ Gibby 335, I wouldn't do it, but it's a $300 used Epi Dot that was bought purely for playin', so the impact on resale value is a non-issue for me. With a bit of care in doing the switch installation, I think it will look just fine. I bought a black DPDT mini-toggle, and it will mount just under the bottom edge of the pickguard (see mock-up below). Should be very unobtrusive there, and will blend right in with the color scheme of the guitar.

If this works out as well as I hope, who knows? Maybe I'll swap the neck volume pot for another push/pull and add either coil-cut or series/parallel capability for that p'up, too!

Attachment 421

[Spudman***]

I didn't realize what guitar you were doing this to. Aren't those a pain to work on the electronics? Yes, simple would be better.

[duhvoodooman***]

Aren't those a pain to work on the electronics?

Amen, bruddah! You have to tie string or fishing line to all the pots & switches, then detach them and pull the whole wiring harness out through the f-hole! Not all that difficult, just arduous and time consuming....