Tone. It’s more than a knob on our guitars, or is it?  For many it’s a quest that lasts a lifetime changing amps, pedals, modding our guitars, and eliminating things like long cables and cheap gear that “rob tone” If these things steal our tone, and what we want is MORE tone, why don’t we just turn up our Tone knobs and get more? If that’s not enough, why not get a Tone knob that “goes to 11”? That’s just not the way things work…. so how DO they work?

First let’s get down with some vocabulary. Tone IS a knob on our guitar, but it does little to shape the actual voice of our instrument, which is properly called: Timbre.




the character or quality of a musical sound or voice as distinct from its pitch and intensity.

Timbre is the word we use to define the difference between a trumpet, a piano, or the human voice. All could be producing the same note at the same volume level (equal frequency and equal amplitude) but sound entirely different. It’s the same way we know Carlos Santana from just a few notes of his playing. So it could be said that Carlos has excellent Timbre. This is the quest of most guitar players, to find their own timbre. So what DOES that Tone knob do?

The Tone circuit can be thought of like a treble-bleed circuit. In most guitar’s circuits the tone pot comes into the signal post-volume pot and affects the signal on it’s way out to the output jack. A capacitor is used as the key component of this circuit. Capacitors are devices made for storing electricity in a circuit but when an AC signal such as our guitar signal is passed through them, they will attenuate or block the low frequencies and let only the highs get through.


It is true that caps let highs get through and not lows. So, what we do is take our guitar signal, right before it goes to the output jack, and shunt it to ground through a capacitor and a variable resistor. That variable resistor is our Tone knob. The more we open up the Tone knob (turn it down) the more of the guitar signal is allowed to touch the cap. Which frequencies get let through is determined by the capacitor's numerical value. A .047 will allow more frequencies to get through than a .015 will. The result is that a .015 is a brighter cap and the .047 is a warmer or darker cap. .022 is a common choice as it is the middle number of the most common values of .015, .022, and .047. The cut-off frequency of these caps is variable to a degree by the forward voltage in our guitars resulting in a less consistent but more musical roll off of treble frequencies.  While we don't have a lot of voltage in our guitars (roughly ¼ to half a volt AC) it IS enough to vary this cutoff frequency of the capacitor. The way this cutoff frequency moves is determined by the capacitor material type.  There are many different cap material types available ranging from affordable to uber-expensive unobtainium vintage caps made out of everything from Mylar to Polyester, paper-in-oil, paper-in-wax, and ceramic. Don’t be too quick to dismiss a material type based on application. Just because from 1956-1960 Les Pauls came equipped with paper-in-oil doesn't mean it’s the be all and end all sound. Jimi Hendrix’s famous Strats had ceramic caps which today are regarded as cheap and dull sounding. His was good and the old vintage ones were too. As I type this, Purple Haze comes on the radio.

A good Tone circuit in a guitar should be one that can produce a wide variety of usable sounds to it’s player and doesn't always sound best at 10. If your guitar only sounds good with your controls maxed out...Perhaps you are looking for a sound your circuitry doesnt produce….YET!!!  Work that Tone Circuit!!