Pickguard wiring debug and question

monchavo

Junior Member
Messages
59
Hello Warmouthers! My next build uses a gorgeous Warmoth roasted maple Strat headstock Pro neck with some very tasty thick and tall stainless wire. The body is an MJT reliced strat-shape. The pickguard and electronics are ... unusual and I humbly request the collected wisdom here to help guide me. I have included a wiring diagram of what exists already plus my goals.

Wiring Digram HSH Blue Strat.png


Pickups and electronics:

  • Neck and Bridge Humbuckers from a 1982 Kawai Acquarius.
  • Middle Pickup is a single coil stratocaster middle pickup, custom wound by Chris Hernandez Pickups, marked 5.78k “CW” B400 A4
  • Volume is an early 80s Japanese pot
  • Tone A is a modern Alpha pot (as yet unconnected)
  • Tone B is an early 80s Japanese stacked coil tap pot.

The pickups, volume and tone B have been directly transferred from the donor guitar into this scratch plate. The five way switch is an Oak Grigsby.

The coil tap when UP put both humbuckers into tapped mode in the donor guitar. I wish to retain this on the new setup.

Wiring configuration commentary (to match the enclosed diagram)

Neck Humbucker

Bare Ground is connected to the body of the coil tap

White Wire (shown as a blue dashed line on the diagram) is connected to the body of the coil tap

Black Wire is connected to lug 5 on the coil tap

Red Wire is connected to lug 4 on the coil tap



Middle Single Coil

White (shown as a blue dashed on the diagram) is connected to L2 on the 5 way switch

Black is connected to the VOL ground.



Bridge Pickup

Bare Ground is connected to the body of the coil tap

White Wire (shown as a blue dashed line on the diagram) is connected to the body of the coil tap

Black Wire is connected to lug 6 on the coil tap

Red Wire is connected to lug 3 on the coil tap



Coil Tap

Lug 5 is connected to LEFT 1 on the 5 way switch

Lug 6 is connected to LEFT 3 on the 5 way switch

~

I wish to:

Goal 1: Add Tone A to the circuit and enable it to control the tone sweep of the middle pickup and add an appropriate capacitor to enable this

Goal 2: Prevent Tone B from being able to adjust the tonal control of the Single Coil middle pickup.



Questions:

  • What wiring changes to I need to perform to achieve the above goals
  • What wiring changes do I need to correct any issues or miswiring in the existing setup
  • Don't I need the pots grounded together with a wire connecting them to the ground?
Cheers fellas

monchavo
 
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I have a question for you about the tone control: Did you try the stock wiring arrangement with single tone control on the 'Donor' guitar, and what issues / shortcomings did you find? It's really common to find HSH guitars that have the master tone arrangement. There sometimes may be issues depending on the pickups used.

I noticed your drawing has some inconsistency. You wrote neck humbucker has the "Red Wire is connected to lug 3 on the coil tap", but the drawing shows it wired to lug 4. There is a similar issue with the connection of the bridge humbucker on the drawing.

Yes all the grounding points need to be connected together, including the ground lug on the volume control. It is sometimes done using metal foil or some low-end guitars, but that is not ideal IMO. Even when using metal foil, I suggest to add some wire links soldered between all the grounding points. Instead of using the case of the toggle switch as a ground point you can consider making the ground connections at the back of the control pots instead. Once all grounding points are solidly connected together, you can choose the location that is gives a convenient and neat installation.

For your question about adding a tone control, it is not an easy one to solve using the standard 5 way blade switch. Just like a Stratocaster, you will be doubling-up of the tone controls in the notch positions #2, and #4 where both tone controls are active at the same time. If you are happy with that, then it's possible to use the standard 5 way blade switch. If you want a custom setup that has individual selection of tone controls in each position, then you need something like the 'Fender Discrete blade switch' or the '4-pole super-switch' often used for custom wiring schemes.
 
I have a question for you about the tone control: Did you try the stock wiring arrangement with single tone control on the 'Donor' guitar, and what issues / shortcomings did you find? It's really common to find HSH guitars that have the master tone arrangement. There sometimes may be issues depending on the pickups used.

I noticed your drawing has some inconsistency. You wrote neck humbucker has the "Red Wire is connected to lug 3 on the coil tap", but the drawing shows it wired to lug 4. There is a similar issue with the connection of the bridge humbucker on the drawing.

Yes all the grounding points need to be connected together, including the ground lug on the volume control. It is sometimes done using metal foil or some low-end guitars, but that is not ideal IMO. Even when using metal foil, I suggest to add some wire links soldered between all the grounding points. Instead of using the case of the toggle switch as a ground point you can consider making the ground connections at the back of the control pots instead. Once all grounding points are solidly connected together, you can choose the location that is gives a convenient and neat installation.

For your question about adding a tone control, it is not an easy one to solve using the standard 5 way blade switch. Just like a Stratocaster, you will be doubling-up of the tone controls in the notch positions #2, and #4 where both tone controls are active at the same time. If you are happy with that, then it's possible to use the standard 5 way blade switch. If you want a custom setup that has individual selection of tone controls in each position, then you need something like the 'Fender Discrete blade switch' or the '4-pole super-switch' often used for custom wiring schemes.
JH, thanks for your reply- smashing stuff.

First off - there were no issues in the donor guitar and the old circuit only had one tone in it. I am adding a second tone in the new guitar for no good reason other than I have three holes in the new pickguard (a custom one was twice the price, and I have a spare Alpha pot - so... why not?)

1) Thanks for spotting my stupid error. I have corrected the text. Both the text and the diagram show the actual arrangement.

2) Thanks for confirming the grounding together - I have soldered link wires before and feel comfortable doing that.
3) Thanks for your second tone comment.

What wiring configuration changes do I need to make to add the second tone?

(Creative bit:: On reflection - I don't actually *need* a second tone, but am loth to have an open hole or a dummy pot there, so would be open to other suggestions around what else I could do. ))
 
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When wiring the toggle switch for coil splits, it should have the red and black wires from each pickup attached to the each side of the switch: Neck wires to lugs 3 and 5, Bridge wires to lugs 4 and 6. If it is actually connected as you drew in your first post, it seems it would not work as a coil split. Instead it would connect the neck and bridge pickups together, which would be really odd.

I drew a diagram connecting the two tone pots. It is a basic Strat wiring diagram, and you will see some variations on other diagrams showing where the capacitor is connected on each lug on the tone pots, but they generally do the same thing as there is more than one solution. The lug you identified as "r2" is where you need to connect the tone control for the bridge pickup. My drawing shows a link from "r2" to "Tone B" which is the pretty standard, but you can link it to "Tone A" instead. For my drawing I made the following connections, although its not exactly as you asked.

Pos1: Bridge (Tone B)
Pos2: Bridge + Middle (Tone B)
Pos3: Middle (Tone B)
Pos4: Neck + Middle (Tone A + Tone B)
Pos5: Neck (Tone A)
 

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When wiring the toggle switch for coil splits, it should have the red and black wires from each pickup attached to the each side of the switch: Neck wires to lugs 3 and 5, Bridge wires to lugs 4 and 6. If it is actually connected as you drew in your first post, it seems it would not work as a coil split. Instead it would connect the neck and bridge pickups together, which would be really odd.

I drew a diagram connecting the two tone pots. It is a basic Strat wiring diagram, and you will see some variations on other diagrams showing where the capacitor is connected on each lug on the tone pots, but they generally do the same thing as there is more than one solution. The lug you identified as "r2" is where you need to connect the tone control for the bridge pickup. My drawing shows a link from "r2" to "Tone B" which is the pretty standard, but you can link it to "Tone A" instead. For my drawing I made the following connections, although its not exactly as you asked.

Pos1: Bridge (Tone B)
Pos2: Bridge + Middle (Tone B)
Pos3: Middle (Tone B)
Pos4: Neck + Middle (Tone A + Tone B)
Pos5: Neck (Tone A)
Thanks for your commentary. The push/pull pot on the tone is wired exactly as it came from the factory back in the early 80s. I completely acknowledge that it's a very odd setup but it does appear to cut the output of the humbuckers in its current setup.

I will check out your suggestions for tone - once again thank you for your response.
 
If you still have the original pickups in the Donor guitar, it may help to analyse the wiring scheme. The usual method for testing is to tap on the poles of the humbuckers with a screwdriver. If the coil is selected, you can hear the noise though the amp. That will indicate if it is working as a coil split switch, or if there is something more complex going on.
 
If you still have the original pickups in the Donor guitar, it may help to analyse the wiring scheme. The usual method for testing is to tap on the poles of the humbuckers with a screwdriver. If the coil is selected, you can hear the noise though the amp. That will indicate if it is working as a coil split switch, or if there is something more complex going on.
I tested it with a screwdriver and indeed the coil tap when UP does produce a thinner sound and you can hear the noise when tapping it through the amp.

For the second tone:

Can I use a second capacitor rather than unsolder the very old one on the tone pot and adapt it?
 
When testing coil-split wiring by tapping with a screwdriver, the idea is to figure out which of the two humbucker poles is active. If the coil-split is active, either the screw coil or slug coil would be dropped out of the circuit. If your doner guitar demonstrates that behavior, it suggests the push-pull control is operating as a coil-split. From the wiring scheme you posted it's not certain whether it is a coil-split or something else, so that can be tested as one possibility.
 
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Of course you can replace the capacitor. That's a good dea. I would rather use one capacitor for Strat style guitars, as having two capacitors will take away some of the brightness in position 4 (neck/middle). One capacitor is the normal way that Strats are wired.
 
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