Guitar Wiring Explored: The Spin-a-Split Mod

Posted on by Richard Irons

In a previous article we looked at how to rig up a simple switch to split a humbucker to a single coil. This gives two very different sounds. But wouldn’t it be nice if we could choose not just those two sounds, but anything in between as well?

This is where the Spin-a-Split modification comes in. It gives you a control on your guitar that gives you a humbucker sound at one end of its range, a single coil sound at the other, and an infinite blend of the two as you turn the control through its sweep. And the best thing is, it’s not even hard to do!

Let’s take a look at a wiring diagram. This is for just one humbucker:

As you can see, the green and bare are grounded as usual, and the black is still used as the output hookup to either the switch or the volume control. The interesting thing is what we’ve done with the second pot (marked “SPLIT”). Our red and white wires are connected to the middle lug and the right-hand lug is grounded.

So when the pot is turned all the way down, the red and white wire will be connected directly to ground – a normal coil split setup. And when the control is turned all the way up, they are not connected to ground at all – a normal humbucker setup. But wait – in fact, they are of course still slightly connected to ground, just with a large resistance (500K if a 500K pot is used).

A good way to get rid of this slight lingering connection to ground would be to use a “no-load” tone control. These are widely available, and remove the connection entirely when the control is turned all the way.

This can give us a huge range of sounds to work with and is another useful weapon in the guitar wiring tech’s arsenal!

Here’s a great video that demonstrates the sounds available when a spin-a-split control is connected to a Seymour Duncan Hot Rails pickup.

As you can see, the in-between sound mixing single coil and humbucker sounds is very usable. It gives us some of the single coil bite and snarl, without losing so much of that throaty humbucker roar. If there is just a little bit of overdrive in full humbucker mode, then it’s likely that rolling back on the spin-a-split will allow the sound to clean up a little too.

Have you got the spin-a-split mod on any of your guitars? What do you use it for?

Written on July 14, 2013, by Richard Irons

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Comments (16)

  • Richard Irons 6 years ago

    I’ve been doing this since the 80’s. The 500K pot is definately not the best choice.

  • Richard Irons 6 years ago

    What about active pickups?

  • Richard Irons 6 years ago

    I use a spin-a-split on a P-rails neck pickup. I like the clean single coil sound and the slightly hotter P90 sound, but the humbucker (both P-rails pickups) is just too much. With the spin-a-split, I can get “just enough” humbucker combination for the sound I need. Highly recommended!

  • Richard Irons 6 years ago

    I’m wondering if this can be done with a pair of p90’s?

    • Richard Irons 6 years ago

      Well, since those are both single coils, you could get the same effect by putting your selector switch to the middle position and turning one pickup down…

      • Richard Irons 6 years ago

        With both pickups on, the volume control will not specifically roll down one pickup, as the middle position has both pickups and all pots on one circuit

  • Richard Irons 6 years ago

    How do you do this if you have 2 pups BUT only 1 Vol and 1 Tone……..

    • Richard Irons 6 years ago

      You could use concentric/stacked potentiometers, giving you four controls in the space of two. Danelectro guitars and some of the earliest Jazz Basses used controls like this.

  • Richard Irons 6 years ago

    Es 345, 1968. I’m installing 2 pearly gates and have ordered a 335 pre
    wired harness. I’m removing the chokes and varitone and going mono. I
    want to put a rotary switch in the varitone hole to allow me to have
    both pu available in series in pos. 1 and then have both pu available in
    parallel in pos 2. I want to keep the pu toggle to select the neck
    bridge combo as is typical and want it to interact with the rotary. Basically it would be as if I installed the SD ring switches and then wired it up 50s style for the rest of a 335 type. I bought a 6 pos 4 pole rotary switch from
    stewmac and was hoping that might do the trick. Can this be done?

  • Richard Irons 6 years ago

    I use ducan pickups almost exclusively … anyhow with regards to passive pickups and 9v powered active artec type components… etc. lots of wiring diagrams out there but I can’t find any that show more than one component… what I want to do is use the Artec QDD variable gain with a MOD board analog delay and a passive Artec 5 way tone switch… anybody got a basic approach to using more than one 9v. onboard gimmick …. do I only need one battery for the whole setup ? etc. pretty soon I’m going to just start wiring stuff together and see what happens !!!

  • Richard Irons 6 years ago

    The temptation to me is to use this on a strat body with 3 mini humbuckers, so like the old les paul standard with volume & tone for each pickup, you get seperate volume & tone for all three, but each as a spin-a-split.

    Then I start thinking of ways to do something similar, without the spin-a-split, but with (somehow) the abiluty to use the humbuckers (all 3) as single coils or as humbuckers (normal) where the complication is getting them to work as : HHH, SSS, HSH – – with a 5 way so you can select your pickup combination (not uncommon) or more like a variation on a les paul standard (how many pots? 6? maybe use doubles so the same knob is both tone & volume on each pickup)… and by then my head starts to hurt just thinking of the wiring diagram. I had a hypoxic brain injury 19 months ago & my ability to handle complicated boolean logic in a circuit (or a computer program) has decreased. 25 minutes being mostly dead scrambles the brain a bit.

    I should bread board it out with lights (instead of sound) to muck about.

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