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....

[Nelskie]

Fancy humbucker wiring, eh? You mean like the "fancy wiring" that was done on your Les Paul's Pearly Gates bridge p'up . . . ?

Sorry DVM, I just couldn't resist. Let me know how it sounds when you get it re-wired.

[Spudman***]

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....

Now I know why it's called an "f hole." Tee hee.

[duhvoodooman***]

UPDATE: The diagram below shows what I've decided to do with the pickup wiring in my Epi Dot. When completed, this wiring scheme will give me:

1. Series/coil-cut/parallel bridge pickup selection through the added 3-way DPDT "on-on-on" toggle switch. This will be mounted into the guitar body just above the bridge volume control.
2. Ability to run the two humbuckers in or out of magnetic phase via a push/pull pot on the bridge volume control (a.k.a. the "Peter Green mod")
3. Series or coil-cut selection for the neck pickup via a push/pull pot on either the neck volume or tone control. Doesn't matter which, really, so I'll probably use the neck tone pot, because there are fewer connections to re-solder.

That gives 17 possible combinations, as I count. Should be interesting exploring the tonal ramifications!!

Here's the diagram. Note that the wire coloring shown is for a Seymour Duncan 4-conductor humbucker. Other makes may use different color schemes (DiMarzio definitely does!), so consult your p'up manufacturer's literature or website, if you do this kind of thing!!

Attachment 446

[Nelskie]

That gives 17 possible combinations, as I count. Should be interesting exploring the tonal ramifications!!

Tonal ramifications!! You'se be sayin' 'dem big words, and I'se gets all dizzy in muh head!

Anyways, it sounds like some big "doin's" are on the board for the Dot. Looking forward to hearing your take on the results!

[duhvoodooman***]

Fancy humbucker wiring, eh? You mean like the "fancy wiring" that was done on your Les Paul's Pearly Gates bridge p'up . . . ?

Yeah, you're just a whole bucket full of laughs there, N-man!

Just to keep this from being an "in joke", anybody who's interested can read this pathetic little tale of woe HERE....

[duhvoodooman***]

I've finished the pickup wiring modifications on my Epi Dot, as shown in the two photos below. I opted not to install a coil-cut push/pull pot for the neck p'up until I had the bridge p'up done and had a chance to fully assess the tonal impact. To summarize what I did:

1. Installed a used Seymour Duncan SH-4 "JB" model 4-conductor humbucker (purchased on eBay) at the bridge. The 4 conductors are necessary to do the fancy wiring described below. The bridge p'up that came in the guitar sounded very good, but was a single-conductor braided shield model that didn't allow these wiring modifications.
2. Wired the JB to a double-pole/double-throw (DPDT) 3-way mini-toggle. This switch is what's called an "on, on, on" configuration, in that it is active in all 3 positions. By wiring it as per the diagram below, you end up with the ability to run the two coils of the humbucker in series (the normal way), with just the screw coil (i.e. "coil-cut" mode), or with the two coils in parallel. All three have a different tone, with the trend from darker & fuller to brighter and thinner. Series and parallel mode are hum-cancelling, but coil-cut is not, since you've essentially turned the humbucker into a single-coil.
3. Wired the outputs of the DPDT 3-way to a 500K push/pull pot that I replaced the stock bridge volume pot with. By cross-wiring this switch, you can change the polarity of the bridge p'up wiring and thereby run the bridge and neck either in or out of phase magnetically. Out-of-phase gives a thinner, almost hollow sounding tone. This mode is what is often referred to as the "Peter Green modification", since the legendary Fleetwood Mac guitarist accidentally re-assembled a humbucker with the magnet poles reversed, making it permanently out of phase with the other humbucker in his LP. Using the push/pull pot allows me to choose which phase mode I want. Obviously, this only works when you're playing from both p'ups simultaneously. The switch position makes no tonal difference if you play only from the bridge, or only from the neck, for that matter.
4. Rather than drilling a hole in the top of the guitar for the new 3-way toggle, I glued it to the underside of the pickguard down at the bottom, directly above the f-hole. The suspended nature of the pickguard mounting that Gibson/Epiphone generally uses allows this to be done. You can see it in the close-up photo below. It's tucked out of harm's way there, but is still easily accessible. I used a hot glue gun for the bond, and it seems to be attached very firmly. I bought a black toggle switch that blends right in with the guitar's color scheme. And the best part was that no permanent alteration of the guitar was necessary!
5. Switched from those knurled chrome Tele knobs the previous owner had installed to proper black Gibson-style speed knobs.
6. Since I already had the pickguard off for the wiring mods, I did the shielding thing with glue and aluminum foil on the back side. Should solve the static build-up issue I've had intermittently.

Attachment 468 Attachment 469 Attachment 470

A word of warning--the wiring mods are not particularly easy things to do, involving some very fine soldering work with small components and tiny wires and contacts. I had a couple of "do-overs" to fix mistakes and poor solder joints before I got everything to work properly. I would estimate that I put a good 6 to 8 hours or so into this, but I'm sure a more experienced person could do it much faster. But it was fun, and an excellent learning experience!

Doing this work on a semi-hollowbody made it significantly more difficult, because there is no access to the inside of the guitar. Consequently, you have to unfasten and remove the entire wiring harness (4 pots, the original 3-way toggle, and the output jack) through the f-hole. Major pain in the butt! The trick I came across was to fasten a couple of feet of string to each component before removing it, leaving it trailing through the mounting hole in the body. Then, when you're done with the wiring work, you can pull the various components back through the mounting holes using the string. Otherwise, it would be a nightmare to get them back in!

By the time I finished the work and got the guitar reassembled last night, my family was in bed and I couldn't play the guitar through any of my amp speakers. But I did a quick run through the various switch positions using the headphone jack on my AD30VT. Very, very interesting range of different tones! I'm really looking forward to cranking it up over the weekend, and will hopefully have the time to record some clips and post them here. But at this point, I have to consider the project an unqualified success. I got all the new tonal options I wanted, the guitar looks even better than before, and I was able to avoid drilling into the body. WOOT!!!

[Nelskie]

Awesome post there, DVM. Glad to hear it all worked out for you. I'm a big fan of the Peter Green tone, too, so I'm anxious to hear those sound clips. BTW - just how many tone settings do you have with that guitar now? Like (27) - or thereabouts? Man, it makes my head spin just thinking about it!

[duhvoodooman***]

BTW - just how many tone settings do you have with that guitar now? Like (27) - or thereabouts?

Nah, only 10. But I think that should be enough for a while!

[duhvoodooman***]

I'm really looking forward to cranking it up over the weekend, and will hopefully have the time to record some clips and post them here.

Links to two sound clips below. Comments on what they are & how they were recorded:

Both clips were recorded on my Delta Blues. The first is a comparison of the three toggle positions for the bridge p'up. In all cases, the same basic riff is repeated three times, first with the coils in series, then coil-cut (i.e. screw coil only), then in parallel. Some riffs are recorded clean, and others use my Digitech Bad Monkey for some overdrive.

The second clip demonstrates the in-phase/out-of-phase modes of the two pickups. The riffs are in pairs, with in-phase as the first. The final two pairs were recorded with the bridge pickup at the parallel coil setting; as you'll hear, this gives the brightest and thinnest out-of-phase tone, with a distinct nasal quality.

I can see I'm going to be tone farming with this puppy for quite a while!

Clip #1

Clip #2