07 October 2013

Wiring DIY: 3 single coils in series/parallel in any combination, with 3 switches


I am going to gift you with a real pearl of wiring designs.
For a very long time, I've tried to be able to run the three pickups of a Stratocaster in parallel or series, on demand and, the design always hited the same stone: when some of two pickups that should be in series is inactive then, the series link breaks and we get no sound.

For some years, I gave up trying it again but, thanks to a reader of this blog, that was looking for such a solution, pushed me to re-think everything again.
We crossed few mails and, he was giving me the last  key (even that he didn't realized about it) to complete the puzzle.

Since the last key was given from outside, I am glad to share this design with you all, for your use and convenience.

Even that this basis mod or module is intented to be used with the three single coils of a Strato, there is nothing that avoids you to use it with any other type of pickup (humbuckers, mini-humbuckers...) and, you can combine it with other mods (OOP, bypass, etc) with ease.

I will present first the basis diagram for this mod, including some comments that will help you to understand what's going on there and, later, I will include some sample diagrams on how to apply this tricky wiring design.
I hope you will appreciate it.


Please, click on the diagram to see it at full size.

This design works with the help of three 4PDT on/on/on switches. Each one allows to switch off the pickup (center position) or to add the pickup to a parallel path (down position) or to a series path (up position).
Parallel path is being represented here in Orange. Series path in Pink. Ground is being represented in Dark Blue and, the path represented in Purple is the tricky part (the last key) of this design.
The Purple path allows me to delay the decision on when to ground a pickup, depending on the status of the rest of pickups.

On left hand, you can see which combos are being obtained depending on the positions of the three pickup switches.
The tricky part is always the series path. If you have a pickup assigned to the series path and one more the the parallel path, that series combination cannot happen so, you should run both pickups in parallel. To be able to put two pickups in series, both should be assigned to the series path, therefore, when just one pickup is in that series path, it will work in parallel (since there is no one more pickup to stablish the series link).

This design has two output spots, that you can see in the upper switch and, that correspond to both differentiate paths. For sure, you can jumper both outputs to have a single output or, you can send each path to a different input, if you wanted separated controls (by example, different value pots) for each path.

Even that this mod is related to three single coils in this diagram, nothing avoids you to use it with any kind of combination of humbuckers and single coils as SSS, HSS, HSH or HHH.

In principle, this three 4PDT switches substitute any blade switch used to select pickups combinations and, allows you to combine the three pickups alone, two of them or three of them in any parallel/series combination what at the ends will give you all the following possible combinations:

Neck alone
Neck in parallel with Middle
Neck in series with Middle
Neck in parallel with Bridge
Neck in series with Bridge
Middle alone
Neck in parallel with Middle in parallel with Bridge
Neck in parallel with Middle in series with Bridge
Neck in series with Middle in parallel with Bridge
Neck in series with Middle in series with Bridge (the three in series)
Middle in parallel with Bridge
Middle in series with Bridge
Bridge alone

And all this is compatible with any other mod, as coil-splitting if you have some humbucker around, by example.

This is a very powerfull mod that can be achieved by removing your blade switch and installing 3 x 4PDT on/on/on switches instead (just drilling de slot that was taking your blade switch).
But, this makes sense for guitars that doesn't need a quick on-fly switching, because to get one of the three single coils alone, you should put off the other two. Just take this into account.
If you are going to use one sound for a song or, you can take a rest between you need one or other pickup combination then, yes, this is a very versatile combo, that could work great for Studio works, by example.

Application Examples

As always, applications are so wide as our needs or willings but, here you are some few examples on how to integrate this mod in some typical situations.

Mod 1 - Single output, Master Volume and Tone

For most super-stratos alike guitars, where you only need a master tone and volume, both output paths are linked together and routed to a volume and tone controls.
For sure, any pickup layout is possible: SSS, HSS, HSH or HHH.
One possible useful mod would be to have a bridge-on switch (a pull/push) that will give you the bridge pickup alone (instantanelly), independently of which combination of pickups is actually seelected in the three switches. Pushing back that bridge-on switch will return you back to the current switch selection. I think that this can be of great use when you want to soloing for a while and return back to your basis sound.
Same bridge-on mod can be of help for rest of example mods presented here.

Mod 2 - Separate outputs, separate volume and tone controls

This is an example on how to handle with different controls each output.
For each path (parallel and series) we are using an stacked pot that allows you to control the output volume and tone for each path. In that way, we could use different pot and cap values for each path because pickups in parallel are a brighter sound than pickups in series.
The output could be even separated for an stereo jack, to run each path output in a different amp, by example. Interesting?.

Mod 3 - single output, independent volumes by pickup

In this example, we are using a dedicated volume control for each pickup that will allow us to blend the exact amount of each pickup in the mix. This would give us a wide range of nuances of parallel and series sounds.
Be carefull to not completly roll off one of the volumes when two or more pickups are in the series path, because that could lead you to no sound. Use the central positions of the switch to remove a pickup from the path, don't roll off it's corresponding volume, instead.
Well, you can use here stacked pots to have independent tones, as well.

Mod 4 - single output, independent volumes and tones

Well, this is as mod 3 but, having indpendent tones by pickup, also. Nice?.
Did you ever dreamed with such a complete control over your Strato sounds?.

Mod 5 - Single output, master volume and tone and bridge-on switch

And, here we are an example on how to integrate the bridge-on switch with a master volume and tone.
This bridge-on switch will let you to instantanely select the bridge pickup (for soloing, by example), independently on which combination of pickups do you have actually selected with the other three switches.
When switching off the bridge-on switch, whichever it was the combination of pickups in those three other switches will come back.
A trick is to change pickups combinations (in those three switches) while you are soloing if you plan to change to a new sound when switching off the bridge-on switch.

So, imagine you had selected Neck alone, you switch on the bridge-on switch and you get Bridge alone. While you are in bridge alone, you can change the other three switches (without affecting your bridge alone sound) to neck in series with bridge, by example. When you switch off the bridge-on switch you will go for neck in series with bridge instead of the neck alone sound where you came from, by example.

Final consideration

I hope you can appreciate the power of this mod and the beautiness of its tricky design.
As it can be applied to any pickup layout (SSS, HSS, HSH, HHH) and, it's compatible with any other mod, the playing ground is huge, as big as your imagination and needs.
I don't recommend it for direct situations where you need to quickly select the right pickups combinations on-the-fly but, it's a wonderful weapon for studio guitars, where you want a broader array of tones available on demand.
Imagine you have an axe with a couple of Seymour Duncan P-Rails (neck and bridge) and a single coil in the middle and, that you are using the Triple Ring Shots for those P-Rails. Everything together combined with this mod. Can you imagine the versatily of such an axe for studio work?.

Ah, I know, your head is humming now!.
ha ha ha.


  1. Great guide and info. Although I am a very bad guitar techie person, this is a great substance to add on. Thanks!

  2. I was hoping the the diagram (using 3PDT switches) which appeared on the Duncan forum a few months prior to this would function as the above is described. Can you confirm, or detail the differences? Thanks in adavance for your respose~!

  3. What kind of 4pdt switches are needed? In shops i found different pin patterns for the center position.

    1. Here you go. I modified Hermetico´s diagram a little bit. I made 2 different diagrams for 2 different types of 4PDT.


  4. Hi,

    My guitar has a Dimarzio 5 way multipole switch (EP1112) and a Fender S1 volume pot switch (250k), with 3 Fender Texas Specials.

    I would like to achieve the following series/parallel connection:

    S1 off: Standard strat connection:

    pos 1) bridge
    pos 2) bridge + middle (parallel)
    pos 3) middle
    pos 4) middle + neck (parallel)
    pos 5) neck

    S1 on:

    pos 1) bridge x middle (series)
    pos 2) bridge x middle (series) + neck (parallel)
    pos 3) bridge x middle x neck (all 3 pickups in series)
    pos 4) middle x neck (series) + bridge (parallel)
    pos 5) middle x neck (series)

    Could anyone help me with this? I´m searching for the wiring diagram but can´t find it.




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