The Overall Guitar Circuit

I’m often asked for advice on choosing volume/tone pot values for a particular guitar/pickup combination.  My answer is usually “get a selection of component values, and experiment until you find what you like”.

I may also mention some general principals for working with passive guitar circuits: lower pot resistance will sound darker, while higher pot resistance will be brighter; larger tone capacitance will result in a darker sound; higher resistance pickups will be hotter but darker; etc, etc. 

But why?  Honestly, you don’t really need to understand why the different component/value choices make a difference in the sound, as you can generally just experiment until you find a sound that works for you.  However, you may be interested in electronics and want a deeper understanding of why your component choices affect the sound.

I have written before about the tone circuit as a low pass filter, but to understand the bigger picture, it’s important to think about the overall guitar circuit: the pickups (which are coils of wire acting as inductors), the volume pot (which is a resistive load), the tone pot and cap (which comprise a first order filter on their own), and even the cable between the guitar and amp (which is a capacitive load).

I’m no electronics expert, and this stuff can get pretty deep and confusing.  So allow me to direct you to some excellent resources from the experts:

• The Secrets of Electric Guitar Pickups by Helmuth E.W. Lemme.
• Going Deeper Into 250K Vs 500K Pots by Orpheo at Seymour Duncan.

There’s also some interesting examples and discussion here:

• Joh Lang’s article on his low-impedance pickups.
• This discussion thread at The Gear Page