Push/Pull Pots and DPDT Switching Fundamentals

Two devices share one control

A conventional push/pull guitar control combines a rotary potentiometer with a mechanically operated switch. The three resistive-track terminals still perform the pot’s normal task. The switch terminals are a separate contact system; pulling the shaft does not, by itself, tell you how the pot or pickups are connected.

A DPDT switch means double-pole, double-throw: two separate common contacts can each connect to one of two throw contacts. The poles move together mechanically. That description does not require a connection between the poles and does not identify the contact numbering of your particular part.

Identify commons with a meter

Many push/pull switches present six contacts in two groups of three, but orientation and numbering are not universal. In a common layout, each middle contact is a pole common. Confirm that on the actual disconnected switch rather than relying on which row looks central in a photograph.

For one pole, find the contact that connects to one neighbour in the pushed position and the other neighbour in the pulled position. Repeat for the second pole. Record the two contact maps. A continuity check is more informative than saying the switch is on or off because a DPDT typically selects between routes.

Fit is part of the specification

The potentiometer value and taper, shaft type, bushing length, thread, body depth and switch form all matter. A control that fits an SG cavity may not fit the same way in another instrument. Check the pot and switch drawing, available cavity depth and knob compatibility before ordering a replacement.

The Bourns PDB183 datasheet is one example of a documented DPDT push/pull part. Its contact and dimension information applies to that model. It is not a universal drawing for CTS, Alpha or every Bourns variant. Avoid translating terminal numbers across products without verifying their functions.

Choose a complete switching task

Coil splitting can use a pole to route an accessible humbucker series junction toward ground. Relative phase reversal usually needs two poles to exchange two coil-signal connections while leaving the shield grounded. Other modifications require their own complete switching map.

Count the independent routes needed in every state. A six-terminal switch is not automatically capable of every combination of split, series/parallel and phase functions at once. A pot fitted in the tone position can carry a switch function independently of its tone-track wiring, provided the complete documented circuit is retained.

Plan before soldering

• Keep the three pot terminals, metal casing and six switch contacts distinct in your notes.

• Label actual commons and throws using continuity measurements in both positions.

• Check required pickup conductors and keep chassis/shield leads out of signal-reversing paths.

• Inspect clearance so exposed terminals cannot contact shielding or adjacent parts.

• Verify both switch states after assembly before reconnecting the amplifier.

Use the related coil-split and phase guides to understand the intended function before choosing a switch diagram. Supported Generator drawings remain the authority for the configurations they actually expose.

References and scope

Bourns PDB183: switch type, contact drawing and dimensions

Fralin: push/pull switching examples

Seymour Duncan: push/pull installation context

This guide describes passive instrument electronics. Verify the actual part documentation and disconnected circuit before changing a connection. Tool links below are for supported configurations and do not imply that every modification in this guide is modelled.