Push-pull pot wiring

Johnny333 · August 2022

ICBM said:

Yes, that all looks right.

For convenience, you may want to connect the ground end of the resistor to a closer grounded point than the volume pot, which is fine. Even the ground tab on the pull-switch (7) will work, or the pot body.

Still don’t cut the pickup wires short yet in case you get an unexpected phase issue!

Thanks again, I eventually got the chance to wire this up as shown above, however the single coils are barely audible compared to the humbucker. Any ideas what might be causing this?

The pickups gave the following readings with a multimeter:
Neck - 573
Middle - 605
Bridge (split) - 870
Bridge (full) - 1734

hywelg · August 2022

I tried to find the schematic I used on my strat but it appears the website has gone. Guitarnutz IIRC.

I have a push push (far better than push pull IMO) on the volume that puts the bridge PU in series with any other pickup . Very usefull volume boost and a more snarly tone.i them have a push push on the neck tone to coil split the humbucker set so that in the default position it is split. Up is full HB.

Now I deliberately got a Fralin Unbucker so the coil split is a little hotter.

This is the most versatile setup I have tried.

ICBM · August 2022

It’s hard to see in the pics unfortunately. Check for shorts on or related to the single coil tone control, if the problem is common to them (and especially if also in the bridge/middle position).

What are those measurement units? They don’t make a lot of sense unless the decimal is in the wrong place. They should be more like 5.73K, 6.05K etc.

If you’re rewire it again, it would also be better to flip the switch around so the contacts are facing the volume control - when they’re on the other side they’re more likely to short against shielding paint etc on the body.

Johnny333 · August 2022

Thanks @hywelg appreciate the suggestion. I'd like to try to work with what I've got though will keep that in mind for future builds

ICBM said:

It’s hard to see in the pics unfortunately. Check for shorts on or related to the single coil tone control, if the problem is common to them (and especially if also in the bridge/middle position).

What are those measurement units? They don’t make a lot of sense unless the decimal is in the wrong place. They should be more like 5.73K, 6.05K etc.

If you’re rewire it again, it would also be better to flip the switch around so the contacts are facing the volume control - when they’re on the other side they’re more likely to short against shielding paint etc on the body.

Thanks again for your help mate, and apologies for the messy pictures!

The single coil tone control looks pretty clean and separated. As for the measurements, they were actually provided to me by the luthier who helped me build the guitar, but he is not as experienced with electronics. I might get a multimeter myself if that would help but assume you might be right with the decimal place. If that were the case, would those readings seem about right?

Lastly, regarding the switch, could it be that I've put that in the wrong way around and that is causing the issues or should it work either way around? (Other than potential shorts with shielding - FYI this guitar currently has no shielding).

ICBM · August 2022

The switch will work either way round, it’s symmetrical - I just wondered about that as a possible cause, but if there’s no shielding it won’t be. Although to be sure, could there be shielding paint under the body finish? Fender do that.

If the decimal points are in the wrong places the readings could be correct, although I don’t think a JB should be quite that high. It is a loud pickup though…

As a test I would first temporarily disconnect the neck/middle tone control - unsoldering the wire on the middle terminal is the easiest - and see if that fixes it.

Johnny333 · August 2022

ICBM said:

The switch will work either way round, it’s symmetrical - I just wondered about that as a possible cause, but if there’s no shielding it won’t be. Although to be sure, could there be shielding paint under the body finish? Fender do that.

If the decimal points are in the wrong places the readings could be correct, although I don’t think a JB should be quite that high. It is a loud pickup though…

As a test I would first temporarily disconnect the neck/middle tone control - unsoldering the wire on the middle terminal is the easiest - and see if that fixes it.

Thank you, I actually built the guitar myself so can guarantee no shielding paint has got in just yet!

Can have a go unsoldering the neck/middle tone pot. Do I only unsolder the middle terminal (connected to position 1 of the 5-way switch from the schematic) and leave everything else in place?

Johnny333 · August 2022

@ICBM ;Just tried this but seems to not make a difference whether connected or not. I am getting some tap-test response from the single coils, but considerably less than the humbucker. Is that normal?

Johnny333 · August 2022

Just had a look at the original schematic and noticed that when I edited it from the volume push-pull to the tone push-pull I switched the sides of the red/white + green/bare wires from terminals 9/10 to 4/5. Could that be causing issues?

Funkfingers · August 2022

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ICBM · August 2022

Johnny333 said:

@ICBM ;Just tried this but seems to not make a difference whether connected or not. I am getting some tap-test response from the single coils, but considerably less than the humbucker. Is that normal?

Yes. Have you tried it with strings on and actually compared the output volume?

Johnny333 said:

Just had a look at the original schematic and noticed that when I edited it from the volume push-pull to the tone push-pull I switched the sides of the red/white + green/bare wires from terminals 9/10 to 4/5. Could that be causing issues?

If you’ve swapped the sides completely it makes no difference. If you’ve connected the coil split to the resistor it will, but it will (very slightly) affect the humbucker and not the single coils.

Funkfingers · August 2022

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Johnny333 · August 2022

Thanks again both. I haven't tried it with strings on yet so will also give that a go though is does seem like the single coils will be a lot weaker.

Re the wiring, it is exactly as shown in this schematic. Should I swap any of the push-pull wiring around?

Funkfingers said:

Johnny333 said:

Just had a look at the original schematic and noticed that when I edited it from the volume push-pull to the tone push-pull I switched the sides of the red/white + green/bare wires from terminals 9/10 to 4/5. Could that be causing issues?

Whichever pole of the push-pull pot you use, the bare/green pair must go to the terminal nearest the pot chassis. (In this instance 5.) The red/white pair must go the next terminal away from the pot chassis. (#4)

In one of your photographs, there is an unexplained wire in black insulation connected to terminal 9. Where does this go?

Did you mean green 4, red 5 (according to this)? ^

The wire from terminal 9 in the 470K resistor going to earth (on the other tone pot)

Funkfingers · August 2022

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Johnny333 · August 2022

Funkfingers said:

Precisely, Watson.

The lead from terminal 9 is ALWAYS connected to ground via the 470k resistor.

Temporarily disconnect that link. (i.e. Where the insulated wire meets one leg of the resistor.)

Do the single coil pickups now give the expected signal strength?

I suspect that your circuit requires a four-pole, five-way Superswitch. One pole selects the pickups. The second sends the signals to the tone controls. The third brings the 470k resistor into circuit at the appropriate times. I would use the fourth pole to automate the humbucker coil split when the bridge and centre pickups are combined.

Thanks, just tried disconnecting the 470k resistor as suggested but that didn't seem to have an effect on the pickup signal.

I am noticing quite a lot of hum which gets particularly bad if I touch the black wire from volume pot terminal 2 to the input jack but assume that might be normal?

Johnny333 · August 2022

Have just compared a tap test with my regular functioning strat on the same volume setting and the new pickguard is WAY off (much much quieter, including the Humbuckers) so something is still definitely off. Could anything be reducing the entire signal chain?

ICBM · August 2022

If you’ve wired it exactly as you’ve drawn it then it is correct and it will work. It doesn’t need a superswitch

.

If you haven’t tried it with the strings on yet, don’t assume what the output levels of the pickups will be.

Johnny333 · August 2022

Thanks @ICBM, I've just tried it with strings on but the signal is barely audible so somethings not right. I've ordered a multimeter that will be delivered tomorrow. Are there any particularly things I can check with that?

ICBM · August 2022

Is it possible you've overheated one of the pots, or the pull-switch? It won't be the main 5-way, they're almost immune to heat.

Do you get a loud hum/buzz through the amp if you touch the pickup terminals on the switch (with the volume up full)?

Johnny333 · August 2022

ICBM said:

Is it possible you've overheated one of the pots, or the pull-switch? It won't be the main 5-way, they're almost immune to heat.

Do you get a loud hum/buzz through the amp if you touch the pickup terminals on the switch (with the volume up full)?

It could well be possible. I am now armed with a multimeter (and the bare minimum of knowledge how to use it!) but I've determined the following values:

Switch position:

1 = Bridge

5 = Neck

Humbucker (Full)

Pos 1- 16.30

Pos 2 - 4.3

Pos 3 - 16.90

Pos 4 - 16.90

Pos 5 - 16.90

Humbucker (Split)

Pos 1 - 8.19

Pos 2 - 3.43

Pos 3 - 8.50

Pos 4 - 8.50

Pos 5 - 8.50

Neck Pickup

Pos 1 - 5.80

Pos 2 - 5.80

Pos 3 - 5.80

Pos 4 - 2.88

Pos 5 - 5.66

Middle Pickup

Pos 1 - 5.90

Pos 2 - 4.29

Pos 3 - 5.76

Pos 4 - 2.88

Pos 5 - 5.90

Pots

Vol - Terminal 1 - 3 (grounded) = 006k

Tone 1 - Terminal 1 - 3 = 260k

Tone 2 - Terminal 1 - 3 = 534k

My conclusion seems to be that the pickups and 5-way switch are fine but the 500k Volume pot might be broken as the reading is only 6k. Or is that just because terminal 3 is grounded?

Also are there any other connections / resistance levels I should check?

ICBM · August 2022

Before we go any further... I am going to stop helping if you refer to pickups as "pups" again. I'm sorry, it just infuriates me for no known reason, but so much that I can barely read a post with it in.

(Deep breath...

)

The volume pot reads 6K from terminal 1 to 3 because the switch was in either position 4 or 5 when you measured it - you're seeing the pickup resistance, which is in parallel with it.

To check it's working properly, measure from ground to the middle terminal while slowly turning it from 0 up to 10. Keep the pull-switch down (off) and the pickup selector in the bridge position (humbucker) so the 470K resistor is disconnected.

What you should find is that the resistance starts at 0, reaches a peak of about 125K when the knob is at 7 or 8, then falls back to 16K(ish) at 10.

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Push-pull pot wiring

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