This configuration enables splitting of either/both pickups, middle position (using both pickups) in series or parallel and in or out of phase.  In the default positions (switches down) the pickups are standard full humbucking that combine in parallel (when both are selected), and they are in-phase with one another.

Switches control:

T1 and T2 – bridge and neck coil split.

V1 – Middle switch position parallel/series.

V2 – Middle switch position in/out of phase.

When neck pickup is coil-split, the phase switch also switches between pickup coils, adjustable when down and slug when up. Using slug coil with adjustable coil in bridge is hum-canceling since the pickups are out of phase and opposite polarities.

Note that the bridge pickup will not work alone with V1 in series.

Components pictured:

• Two vintage-wired open-coil humbuckers (i.e., two-conductor models).

• Standard three-way pickup selector switch.

• Four push-pull pots (500k Ohms)

• Output jack

Different pickups will have different color codes for the wires.  Consult the manufacturer's website for which wires feed from which coils.  This is a sort of hyprid schematic/diagram.  Only crossing lines with dot are connected. All others are assumed to be separate.

Note: Nate adds that "I've designed this circuit specifically for vintage-wired humbuckers with a hot output, braided shield that's used both as the ground and low output, and a coil split wire.  I just installed Stewart-MacDonald Golden Age vintage-style humbuckers in my Epiphone Les Paul.  The main problem with this circuit is the low output of the neck pup becoming hot when the series switch is engaged, but I’m using uncovered pups, so there’s no grounded cover to cut out the pup if it’s touched, just the pole pieces and height adjustment screws.  It’s less than ideal, but it should work."