The Complete Guide to Guitar Potentiometers

What a potentiometer does

A potentiometer, or "pot", is a variable resistor. Inside is a curved carbon track with a lug at each end. A metal contact called the wiper sits on the track and turns with the shaft. As you rotate the knob, the wiper slides along the track and changes how much resistance sits between it and each end. The wiper itself is a small sprung brush: one end rides on the track, the other on a collector ring that carries the signal to the middle lug.

In a guitar, pots do two jobs:

• Volume: the pot acts as a voltage divider. The pickup signal goes into one outer lug, the other outer lug goes to ground, and the wiper sends a portion of the signal to your output. Turning it down sends more of the signal to ground.
• Tone: the pot acts as a variable resistor in series with a capacitor between the signal and ground. Turning it down lets the capacitor bleed off more treble, which gives you a darker, warmer sound.

Anatomy of a guitar pot

Most quality guitar pots, including the CTS pots found in many US-made guitars, share the same construction. Knowing the parts makes product specs much easier to read.

Shaft

What your knob grips. Either solid (for set-screw knobs) or knurled and split (for push-on knobs).

Bushing

The threaded collar that passes through your guitar and is held by a washer and nut. Its diameter and length decide whether the pot fits.

Phenolic wafer

The insulating board that carries the resistive track and the terminal tab.

Can

The steel housing that shields the pot. Its size is what you measure for "mini" or "full-size", and many players solder ground wires to it.

Solder lugs

The three terminals where your wires connect, riveted through the terminal tab.

How to choose, step by step

Work through these six decisions in order. The first two shape your sound; the last four make sure the pot fits.

The first two choices shape your sound. The last four simply make sure the pot fits.

Quick picks by guitar

Common starting points for popular instruments. Always check against your own guitar, especially imports, which usually need metric parts.

Need the full wiring? See our wiring diagrams for Strat, Tele, Les Paul, SG and bass.

CTS vs Bourns vs Alpha

All three make reliable pots. The right one depends on your guitar, your knobs and your budget.

Whichever brand you choose, a quality pot turns more smoothly, holds its value more accurately and lasts longer than a budget part. For a guitar you play often, it's one of the most worthwhile upgrades you can make.

Specialty pots

These pots hide a switch or a feature inside the same control, so you can add sounds without drilling new holes.

Blend (balance) pots

A blend pot, also called a balance pot, is two pots stacked on one shaft. Each deck has its own track and its own three lugs, and you wire each deck as the volume control for one pickup. It's the classic control on a Jazz Bass with a single master volume, and a neat way to dial in any mix of two pickups.

We call the front deck (nearest the bushing) deck A and the rear deck deck B. Each deck's lugs are numbered like any pot: lug 1 is the end of the track the wiper reaches with the knob fully anticlockwise, and lug 2 is the wiper. Seen from the side with the shaft up, lug 1 is on the left. Seen from the back with the lugs down, it's on the right.

How it blends

Dual-gang pots for blending come in two kinds, and they behave differently in the middle.

• Blend (M/N taper). Each track is resistive for only half its length; the other half is a solid conductor. So each pickup stays at full volume over half the turn and is turned down over the other half. The two decks have their resistive halves at opposite ends, so as one pickup fades, the other stays at full. In the centre both are at full.
• Linear balance. Two ordinary linear (B) tracks, wired in opposite directions. One pickup fades in as the other fades out, and in the centre each is at about half volume, so the mix is a little quieter than either pickup alone.

• Centre detent. Both kinds usually click at the centre, so you can find the halfway point by feel. On a blend pot that's both pickups at full; on a linear balance pot it's both at about half.
• Wiring. Lug 2 of each deck (A2 and B2) goes to the output or the master volume. Each pickup goes to an outer lug of its own deck, and that deck's other outer lug goes to ground. On a linear balance pot the decks are wired as mirror images: pickup A on A1 with A3 grounded, pickup B on B3 with B1 grounded. An M/N pot has its direction built into the tracks, so follow the maker's diagram for which outer lug takes each pickup.
• Blend versus two volumes. Two separate volume pots can do the same job but need two knobs. A blend pot puts the mix on one knob and leaves the other free for a master volume.
• Value. Match it to your pickups like any pot: 250K for single-coils, 500K for humbuckers. Both decks have the same value.
• Check which kind you have. A blend pot is listed as M/N or blend taper. A linear balance pot is listed as linear or B taper, usually with a centre detent. A stacked pot for concentric volume and tone has no detent and isn't meant for blending.

Installation tips

1. Photograph the old wiring first. A clear photo of every connection is the easiest way to put everything back correctly.
2. Check the fit before you solder. Test-fit the bushing in the hole and a knob on the shaft. Problems are much easier to fix before the wires are on.
3. Use the washer and nut. Tighten firmly but don't overdo it. A loose pot will turn in its hole and pull on the wires.
4. Solder quickly. Heat the lug and the wire together and get in and out. Too much heat on the lugs can damage the track inside.
5. Ground to the can carefully. Scuff the spot with sandpaper first so the solder flows, and use plenty of heat so it bonds properly.

Rather not solder? Choose our pre-wired solderless kits, or let us do it with our wiring services.