Tag: wire

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How to Wire a Spin-a-Split Potentiometer for Electric Guitar Humbuckers: A DIY Guide

So, you’re thinking of tweaking your guitar with a spin-a-split potentiometer, huh? Good choice! If you’re ready to take your humbucker tone from thick and beefy to something a bit more single-coil-ish, you’re in the right place. But before we dive in, don’t stress too much—this is actually a super doable mod, even if you’re not a wiring wizard.

What the Heck Is a Spin-a-Split Anyway?

Let’s start with the basics. Humbuckers are known for their warm, fat tone because they have two coils working together to cancel out noise and create a fuller sound. But sometimes, you want that bright, snappy, single-coil sound—without actually switching to a single-coil pickup. Enter the spin-a-split!

A spin-a-split mod gives you the best of both worlds: it lets you blend your humbucker from full-on humbucker mode into a single-coil sound by gradually “shutting off” one of the coils. Instead of a hard switch between humbucker and split-coil, you get a smooth transition that you control with a knob. Pretty sweet, right?

Diagram of how to wire a spin-a-split variable coil tap for electric guitars

What You’ll Need

First things first—gather your gear. Here’s your shopping list:

  • A 500k potentiometer (also known as a pot) for the spin-a-split (logarithmic/audio taper is most common, but linear taper works too, depending on your taste)
  • A soldering iron and solder (get ready to do a little melting)
  • Some heat shrink tubing or electrical tape (to keep things neat)
  • Wire strippers (because you don’t want to do this with your teeth)
  • A screwdriver to get into your guitar’s control cavity
  • The guts to tinker with your beloved axe!

Wiring It Up: Step-by-Step

Alright, let’s roll up our sleeves and dig in.

1. Open Up the Guitar

Pop open that control cavity by unscrewing the backplate (or pickguard, depending on your guitar). Look at that beautiful mess of wires—it might seem intimidating, but don’t worry, we’re focusing on just a couple of them.

2. Find the Humbucker Wiring

Look for the wires coming from your humbucker pickups. They usually have four leads (unless you’re working with older models or simpler setups). If your humbucker has only two leads, this mod might not work without additional wiring to separate the coils. For the four-conductor setup, you’ll have:

  • Hot wire (going to the selector switch) Its Green for Warman
  • Ground wire black and bare wire on ours
  • Two wires that connect the coils in series (the ones we’re interested in)

These two wires connecting the coils are your targets! On our humbuckers these are white and red.

3. Prep the Potentiometer

Grab your shiny new potentiometer. You’re going to be using this to “spin off” one of the humbucker’s coils. Basically, you’ll wire the coil splitting leads to the pot, so when you turn it, you control how much of that coil stays in the game.

Most guitar mods use 500k pots for humbuckers since they give you a nice range of tone options. A lower value would make your split sound too muddy, while a higher value might make the humbucker sound a bit too bright.

4. Wire the Pot

Now it’s time to wire!

  • First, locate the two wires from your humbucker that connect the coils. These are usually color-coded Our Warman ones are red and white.(green and white on many brands like Seymour Duncan, or red and white for DiMarzio).
  • Solder both of those wires to the middle lug of your potentiometer.
  • The outer lug on the pot should be connected to ground (you can usually do this by soldering it to the back of one of the other pots in your guitar). You can also solder the outer lug directly to the back of the pot you’re using if there’s space. Just be sure it’s a solid connection.

When you turn the knob, it gradually takes that coil out of the circuit—giving you that sweet, single-coil spank without any hard switches.

5. Solder Ground and Shield Wires

For clean wiring, attach a small ground wire from the pot case to the common ground in your control cavity. This helps eliminate noise and makes sure everything’s properly grounded. Don’t skip this step unless you love buzz and hum!

6. Heat Shrink or Tape It Up

Once your wires are in place, it’s a good idea to add some heat shrink tubing or electrical tape over any exposed solder points. This’ll keep things from shorting out if the wires move around inside the cavity.

7. Reassemble the Guitar

You’ve done the hard part! Carefully place everything back into the control cavity. Make sure your potentiometer fits snugly into its new home—tighten the nut, put the knob on, and screw the backplate back on.

Final Thoughts: Play Time!

Now, plug your guitar into your amp, turn the volume up, and test out that sweet new spin-a-split control! With the knob cranked all the way one direction, your humbucker should sound as thick and full as ever. But as you roll it back, you’ll notice one coil fading out, giving you a brighter, more single-coil-like tone.

This mod is super versatile, letting you dial in a wide range of tones without committing to a full coil split. Plus, you’ll look cool while twisting that knob mid-solo, like you’re controlling the universe of tone!

Got any questions, or ready to share your spin-a-split experience? Drop a comment below and let’s talk guitar mods!

Rock on! 🎸

This article was written by Josi Warman, founder of Warman Guitars. With over 40 years of experience building guitars, designing pickups, creating custom wiring systems and publishing guitar-building guides, Josi has helped thousands of players upgrade and customise their instruments.

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Basic guitar circuit wiring.

So here’s todays ramblings on how to do some basic wiring up stuff. A fairly simple arrangement of 2 pickups – a neck and bridge – with a there way switch ( both 8 lug lever witch and 3 way toggle switch variants ) with a master volume and tone control.

The diagrams show this done with 2 single coils but the principle is the same for 2 humbuckers but you might want to swap the 250k pots for 500k pots just to let a bit more of the treble through.

As with all pickup wiring the hot / plus / positive – whatever you want to call them – leads go to the switch lugs and the ground / negative / earth leads connect up into the common earth circuit, which also hooks into the bridge earth wire otherwise it’ll hum like billyoh when you aren’t touching the strings.

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Working out humbucker wire colours.

Ah – the dark art of what colour wire goes where !

Well not really, its actually pretty easy to work this out without being given the exact wire colours on a pickup, provided its come straight out of the packet or still wired up as standard. Not rocket science, just a bit of common sense. Heres a photo of our standard end of the wire.

As you can see there are 5 separate wires sticking out the end of the main cable insulation.

Lets take that black one first that is connected to the bare wire. The bare wire is always the overall chassis earth of the pickup and is the one that is soldered to the baseplate of the pickup so its going to have to connect to the earth circuit on your guitar. The black wire is pre-soldered onto it so, here’s the clue, thats the negative wire of the humbucker as we have already connected it to the other earth wire and it needs to connect to the earth circuit of the guitar – that’s kind of why we solder them together before they get shipped out.

You know its a 2 coil pickup, as you bought a humbucker, so theres got to be a connection between those 2 separate coils else the whole thing wont work right ? As you can see there are 2 wires connected up together that aren’t part of the earth connection of the guitar – Bingo – the red and white wires link the 2 coils of the humbucker together.

The leaves us with just one wire unaccounted for and that’s the green. By a simple process of elimination that has to be the output / hot wire of the pickup. Thats the one that’s going to have to go to either your selector switch or the input lug on your volume pot.

Told you it was quite easy to work out.

Gets a little more complex working out which are the hot and negative wires of each coil but its still not rocket science. You already know which is the negative of the first coil – the black wire. You also know which is the positive / hot wire of the second coil – the green wire. Now you’ll need to get some sort of continuity tester or multi meter to help with this bit and you’ll need to separate the white wire from the red. You can usually just pull them apart.

Start by connecting one lead from your multimeter to the black wire ( the negative of the first coil ) and then connect the other lead to either the red or the white wire to see which one gives you a continuity signal. That identifies the hot wire from the first coil – if you don’t want to know the answer without testing then look away now and don’t read this bit – its going to be the white wire on our pickups. You’ve got a continuity signal then between the back wire and the white, so you now know the negative and positive leads of the first coil.

You don’t even need to test for the positive and negative leads of the second coil as you already know that the green wire is the positive lead of coil 2 so therefore the red wire just has to be the negative lead of the 2nd coil.

Also if you want a quick and dirty method of working out which pickup is the bridge and neck, and you can’t be bothered to turn them over to look for the B or N stamp on the back, then matched humbucker pairs have red heat shrink on the end of the cable and neck ones have black heat shrink.

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Basic guide to Warman wire colours on 4 wire humbuckers.

The Warman twin coil humbuckers all pretty much follow the same wire colour codes as follows.

Bare wire. This is the overall group wire for the pickup and needs to be connected to a common earth point on the guitar. Typically this is the back of a pot.

Black. This is the negative ( – ) wire of the first coil, sometimes called the start wire.

White. This is the positive ( + ) wire of the first coil, sometimes called the finish wire

Red. This is the negative ( – ) wire of the second coil. ( start )

Green. This is the positive ( + ) wire of the second coil ( finish )

To wire this up as standard humbucker with both coils i series. Connect black and bare to the back of one of the pots ( common earth circuit )

Leave red and white joined together , they come pre-soldered to each other . Wrap some insulation tape around this solder joint to avoid accidental shorting our of the coils when you stuff all the wires back into the guitar cavities.

Connect the green wire either to the input lug on you volume pot or the pickup selector switch, this will depend on how your guitar is wired and its control layout .

Single coils

Single coil pickups have just 2 wire coming out of them. This will either be a single twin core cable or two individual leads, depending on model. single cable versions have an inner and outer core to the wire, the inner is the hot wire and the outer is the ground / negative wire. If the pickup has two individual leads then one of these will be black, which is the ground wire, and the other coloured lead will be the hot wire.

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How to wire a phase reversal switch into your guitar pickups.

An easy modification to get more tones out of your pickups is to wire in a phase reversal switch. This basically swaps over the signals from your hot and ground wire. A pair of pickups are wired “in phase” where they work in tandem adding to each others signal. When you reverse this signal they start to work against each other “ out of phase” and produce a thinner more trebly tone.

The further the pickup coils are away from each other the better, so this works best for neck and bridge positions. If you tried to do it on the two coils on the same humbucker, putting them out of phase with each other all you would acheive is a very thin, cancelled signal with a massive volume drop. Only one of the pickups needs to be wired with a phase reversal switch. Wiring two pickups this way would acheive nothing . Reversing the signal on both pickups would put them back in phase. End result – zilch tone change.

If you are planning on doing this on a 3 pickup guitar, like a Strat with 3 single coils fitted, then put the phase reversal switch ion the wiring of the middle pickup so that you can have positions 2 and 4 usable with it.

You can use either a standard toggle switch for this mod or a push pull potentiometer.

Its a fairly easy wiring job. First solder the two criss cross wires. Next solder the leads from your pickup to the two end pins of the switch. Finish off by soldering your output wires to the two pins in the middle. Then these two output wires go to your other guitar circuitry.


Job Done !

You can find push pull potentiometers for this job here

Suitable for either single coil or humbucking pickups.
Double Pole Double Throw ( DPDT ) 2 position switch wired for phase reversal.
Diagram shows the view from the underside of the switch body.