Simplified Way to Wire a Spin-a-Split

[blueman335]

Being a big fan of unbalanced coils, I like to either use hybrid PU's or spin-a-splits whenever possible these days. I'm going thru my guitars and converting some with single lead HB's over to spin-a-split and thought of a shortcut and tried it tonight, that makes it simple and quick to do on a single-lead HB. You don't need to rewire the entire PU to 4 lead, and you don't need to take any wires off the volume pot. The process takes minutes.

The PU
- Remove the cover, and pull back the tape covering the wires at the one end.
- There's a wire that runs between the two coils. On Duncan 4-lead HB's, these would be the red and white wires. Carefully take the little piece of tape off that the covers that splice. Don't yank on it.
- Take an insulated wire, long enough to run from the PU to the tone pots, usually 12-15" for neck PU's, shorter for bridges.
- Solder that single wire onto the splice of the wire connecting the coils together, and put the little piece of tape back over the splice. All you did was add one more wire to the existing splice, so that you can have access from the pots.
- Put the covering tape back over the coils.
- I just ran that single wire down one leg of the base plate, and the cover fit back on fine.


The Wire
- Run the wire thru the hole/channel in the body to the controls. In some guitars you'll need to lift out both PU's to do this, in others you won't. I did it to an LP neck PU, and didn't have to lift the bridge PU out, because LP's have a big channel inbetween the PU's for all the wires.

Convert the Tone Pot to a 2nd Volume Pot
- Remove the capacitor and cut the hot wire coming from the volume pot, but not the ground wire.
- Looking from the bottom of the pot, make the lug on the left a ground to the pot case (same as on a volume pot).
- Solder the new single wire you added to the PU, to the middle lug on the tone pot. Nothing is connected to the lug on the right.

You're done. You just converted a single-lead PU to double lead, for spin-a-split (or for a push-pull for coil cut).

[ParameterMan]

Re: Simplified Way to Wire a Spin-a-Split

I'm curious to know how much extra interference that unshielded wire picks up, and/or if it's even noticeable. It's not really in the signal path as it's more of a bleed to ground than anything but it's still an antenna floating there feeding into the middle of the pickup.

[blueman335]

Re: Simplified Way to Wire a Spin-a-Split

I'm curious to know how much extra interference that unshielded wire picks up, and/or if it's even noticeable. It's not really in the signal path as it's more of a bleed to ground than anything but it's still an antenna floating there feeding into the middle of the pickup.

What I used was a shielded wire, and just made the connections with the inner part. I didn't think about the noise aspect, which is why I suggested using a single insulated wire. From that perspective it would be best to use a shielded wire.

I should add that my primary goal with spin-a-splits is add treble and thin out the mids in neck humbuckers, something often appreciated in LP's and 335's in particular. If you have a neck HB that's a bit warm/muffled/bassy/muddy and it's a single-lead, a situation I've run across often enough, this method of adding a spin-a-split is a quick and easy fix. May prevent you from replacing the PU. The limitation to push-pulls for coil cut is that you get one coil or two, and nothing inbetween.

[ErikH]

Re: Simplified Way to Wire a Spin-a-Split

Go one step further and make that pot a no-load so that when it is essentially dialed in to full humbucking mode, that extra lead is not even in the circuit any longer. On a normal pot, there's still some DC resistance going on and it'll shunt some signal to ground. I discovered that when I was playing with spin-a-splits and had my meter on the pot. I also added a 470K resistor across the outer lugs to smooth the taper out (was using a 500K pot).

[ParameterMan]

Re: Simplified Way to Wire a Spin-a-Split

Hurr durr I should mention that my main LP is equipped with dual split pots and I haven't used the full humbucker sound for quite some time. I think more people should try it.

I will note(since I found this info hard to find) that pot values vary dramatically by impedance: a 500k pot is virtually perfect for a JB(~16k) - the effect starts smoothly near the beginning of the rotation but isn't changing the full humbucker sound in any way I can hear(I touched the wire on and off a few times before I soldered it). On the other hand, a 250k pot is too high resistance for a '59 neck(~7.5k) - the first half of the sweep does nothing. I need to break out some resistors and take it to 100k or so and see how that works.