Understanding A500k vs. B500k Pots in Your Guitar Kit

When it comes time to wire your DIY guitar kit, you might notice that the potentiometers (or "pots") included in your hardware pack have different letter markings stamped on the back—typically A500k and B500k.

While they look identical on the outside and both do the job of controlling your guitar's signal, the way they function as you turn the knob is quite different. Here is everything you need to know about what these letters mean and where each pot should go in your circuit.

What Does "500k" Mean?

The "500k" refers to the pot's electrical resistance rating: 500,000 ohms.In the guitar world, 500k pots are the industry standard for guitars equipped with humbucker pickups. Because humbuckers naturally have a darker, warmer tone, 500k pots allow more high-end frequencies to pass through to your amplifier, keeping your guitar sounding clear and punchy rather than muddy.

(Note: If your kit has single-coil pickups, it will likely include 250k pots instead, which tame some of the harsh, bright high-end).

The Difference: "A" Taper vs. "B" Taper

The letters A and B refer to the potentiometer’s "taper"—which is simply the rate at which the resistance changes as you turn the knob from 0 to 10.

A500k: Audio Taper (Logarithmic)

"A" stands for Audio Taper (sometimes called Logarithmic Taper).Human hearing is not linear; we perceive changes in volume on a curve. An Audio Taper pot is specifically designed to sweep along that same curve.

• How it feels: When you roll an A500k pot down from 10 to 8, you will hear a very smooth, natural, and gradual decrease in volume.

• Best used for: Volume controls. Because it mimics how the human ear works, an Audio Taper pot gives you incredibly smooth, predictable control over your guitar's volume swells and roll-offs.

B500k: Linear Taper

"B" stands for Linear Taper.A linear pot changes resistance at a perfectly constant, even rate. If you turn the knob 50% of the way down, exactly 50% of the resistance is applied.

• How it feels: If you use a B-taper for volume, rolling from 10 down to 8 might sound like it does almost nothing, but then suddenly all the volume drops off steeply between 3 and 0. It acts much more like an on/off switch to the human ear.

• Best used for: Tone controls. Because tone control is about filtering frequencies rather than controlling overall output, a steady, linear sweep allows you to dial in specific amounts of treble roll-off accurately.

Standard Wiring Setup vs. Personal Preference

If you are following standard industry wiring diagrams, the general rule of thumb is:

• Volume Pots = A500k

• Tone Pots = B500k

Can they be swapped?

Absolutely! While the setup above is the modern standard, there is no strict "wrong" way to wire your guitar.Some players actually prefer B500k for Volume if they play with high-gain distortion and want to keep their volume at max until the very end of the knob's rotation. Similarly, many vintage guitars (and some modern manufacturers) use A500k for Tone because they prefer a more dramatic tonal shift at the bottom of the dial.

If your pre-wired harness came set up differently than a diagram you are reading, don't panic! It is completely safe to install and play. However, if you prefer the standard sweep, you can always desolder and swap the pots to match your personal playing style.