You would perform this modification
to affect the middle pickup of a guitar with 3 single coils (e.g., a Fender
The illustration shows how to put a phase
reversing switch on a push-pull pot (I don't have the pot wired in this
picture; it can serve any function). You don't have to use a push-pull
pot as any DPDT (double pole-double throw) switch will work.
The bottom configuration (the way it would
be if you had the push-pull pushed) is the normal phase (what I call "in
phase"). The top (pulled) configuration produces a phase cancellation
The (-) wire is the black one. The
(+) is usually red, sometimes white or yellow. The wiring running
to the 5-way switch goes to the same place on the switch as the middle
pickup was originally connected (I didn't bother drawing this as different
guitars have different types of switches).