16 September 2014

Wiring DIY: Hermetico's HH X61 SD mod


Guitar Modded

LP-body with two Humbuckers but, only two controls: master volume and master tone.


  • HH layout, 4 conductors pickups
  • Two Triple Shot rings (Seymour Duncan)
  • 1 Swiftcraft 3-way switch (pickups selector)
  • 1 Master Volume and 1 Master Tone, both with pull/push
  • 1 4PDT on/on switch (blower-switch)

Difficulty Level



  • With all switches off, it provides standard HH tones but, with a single master volume and a single master tone.
  • Volume pot's pull/push switch is being used to put the Neck pickup Out-of-Phase (when the bridge pickup is also selected) and, reverses the split coil (if split).
  • Tone pot's pull/push switch is being used to put both pickups in series (independently of if they are split or with coils in parallel). It overwrites every position of the 3-way (so, you get the same combo in Treble / Middle / Rythm).
  • Triple shots are able to deliver following combinations for each pickup: split north, split south, coils in series and coils parallel, depending on the position of the two micro-switches on the ring.
  • Finally, the 4PDT on/on switch wants to be a "blower" switch (name often used for a feature that allows you to directly with your bridge humbucker, usually bypassing all switching system and controls). In this case, the user wanted to go for bridge full-humbucker but, thru master volume and tone, overwriting the rest of switches in this design.

Wiring Diagram

Click on the picture for full size.


Notes: white wires are being represented in light-blue and, bare wires in grey. Pickup's wire colors follow Seymour Duncan' schema.

The requester for this design was a Seymour Duncan's forum mate, who already had a working solution based in a couple of triple-shots and a serializer and phaser switches.
He wanted to introduce a blower switch, in a way that he could bypass both triple shot rings' switching, both pull/pushes and, the 3-way. He wanted to run the bridge pickup in full humbucker mode but, thru volume and tone controls (not a direct-out, as often is being requested).

There was a discussion saying that this blower switch couldn't be done with just a 4PDT on/on switch and that, a 6-poles switch would be necessary.

I had the impression that it could be done with just a 4PDT on/on switch and, wanted to go into design, achieving a working solution.

The big issue on this design is the Triple Shot system, since it's some kind of black-box, where the switching occurs in background. The inputs for the Triple Shot are the 4 conductor wires of its respective pickup. The outputs of the Triple Shot are a couple of wires (positive-white and, negative-black).

Internally, this is what happens:
  • Coils in series (standard humbucker): green to negative (black), red and white linked together, black to positive (white).
  • Coils in parallel: green and white to negative (black), red and black to positive (white).
  • Split to South: green, white and red to negative (black), black to positive (white).
  • Split to North: green to negative (black), white, red and black to positive (white).
Depending on what do you want to do after coils arrangement selected by the Triple Shot, you should ground the negative wire (black) or not.

In the case of neck pickup, we want to do an out-of-phase if the volume pull/push is up so, we cannot ground the negative before this happens. But, since the negative of the neck pickup could be put in series with the positive of the bridge pickup, when the tone pull/push is up, we cannot ground neck's negative until the serializer switch.
That's why in that phaser switch (tone pull/push), we are just deciding with of the two wires (negative-black, positive-white) will definitively be assigned to pickup's positive-orange, negative-dark green.

In the serializer switch, neck's negative (dark green) goes to ground (if the switch is off) or it's being linked to bridge's positive (white).

The tricky part is all related to the bridge pickup. If that blower switch wasn't there, we would just solder bridge's wires to their respective lug of the Triple Shot and, from there, we would run the positive (white) and negative (black) wires to the serializer, before to decide what goes to the 3-way switch, for pickups selection.

But the blower concept obliges us to route pickup's conductor wires first to the blower switch and, only if the blower is off, from that switch to its Triple Shot ring and rest of switching system.

Another issue introduced with this particular blower concept is that we need to choose between two different sources (whole switching system or just the bridge pickup) as input for the volume and tone controls so, at least, we need one pole to choose what to run to volume's input.

In principle, to completely bypass the bridge's triple shot, we would need 4 poles, one for each pickup's wire. This and and additional pole we need for volume's input makes 5 poles and therefore, this is where the discussion about doing it with a 6 poles switch comes from.

But, If we think on it twice, bridge's green wire will be always ground, directly when the blower is on but, thru the negative of the triple shot when the blower is off, also.
Read above the description of what happens inside the Triple Shot and, you will realize that the green input is always linked to the negative (black) output.

Therefore, I can solder the pickup's green directly to the Triple Shot and, since the rest of wires will never go to their inputs if the blower is on, I'm sure the only thing that will happens inside the triple shot is that the green wire will be always linked to the negative wire, which I have to always ground, in any case. That frees one of the poles and, allows me to play with a 4PDT on/on switch, instead of going for a 5PDT or a 6PDT (usually, rotaries).

Now, let's focus in the blower switch.
Red, white and black wires from bridge pickup go to their own poles (common lug, center lug on each column). When the switch is off (upper lugs, on diagram), each wire is effectively linked to their respective inputs on the Triple Shot, allowing the whole switching system.
But, when the switch is on (lower lugs on diagram), we avoid to send those wires to the triple shot and, we jumper white and red together (to put coils in series) and, we link pickup's output (black) to the input of the volume-tone-jack network.

Last pole is volume-tone-jacks input (in pink). We will choose between the output from the 3-way (upper lug, when switch is off) and the output from bridge pickup alone (lower lug, when switch is on).

Some additional comments.
Since the blower is being implemented with a 4PDT on/on switch, this solution is easily portable to a Fender HH Stratocaster and, we can use Fender's S-1 volume/switch for that blower switch, with will leave us a classy design, without altering the look of the axe.


  1. Very nice diagram!

    I have been thinking about a similar schematic for a long time. However, I have a doubt: is there any problem having both humbuckers in the "coils in parallel" mode and the tone pot's pull/push in the "series" position? Maybe, instead of "a problem", what I am wondering is: do each coil get to be in series with the correlative coil of the other humbucker or what happens?

    I know it is a weird choice, first splitting the humbuckers and then putting both coils in series with the other two coils in the other humbucker, but you can consider it just a theoreticall question.

    Thank you very much for this blog! :)

    1. There is no issue at all. The series switch just puts in series both pickups. Which coils?, that depends on your selections for each humbucker. It can put in series both humbuckers, a mix of both coils, same coils, etc.


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