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
Double Pole Double Throw ( DPDT ) 2 position switch wired for phase reversal.
Diagram shows the view from the underside of the switch body.
how do we know which one of the outputs is hot/ground?
It kind of doesn’t matter because the phase reversal switch swaps the hot nd ground around when it’s operated. In one position the hot is one cable, in the other switch position it switches the hot to the other cable and reverses the phase