Guitar Building Tips with Minimal Tools

The Basics of Pot's | The Basics on Switch Wiring | Bringing the Switch and Pots Together | More Advanced Switching Options

At this point, I assume you have a good understanding of how pickup wiring works. This is where you can now learn how to make those different wirings accessible. I wont pretend like I know about resistances and that kind of thing, because I dont. But I do know how to utilize switches and pots to make a ton of different combinations.

First off, we have a potentiometer, or "pot". The pot is, more generally, the thing that your volume and tone knobs attach to.
There are several types and values of pots out there.
First we will talk about the difference between an "A" pot and a "B" pot. There are more than just these two, but these are the most common.
An "A" pot refers to an "audio taper" which is also known as a logarithmic taper. Basically, the way we hear volume change is logarithmic, so using an "A" pot for a volume pot SOUNDS linear. This is what we want.
A "B" pot refers to a "linear taper", which is useful for a tone control, because it keeps the change in tone sounding linear.

Next lets talk about values. Most common are 250k and 500k. There are also 1 Meg pots which are an even larger value.
The main thing to know here is that a larger number means a brighter tone when the control is up all the way. Generally a 500k pot is considered average to more bridge for a single coil pickup. For a humbucker, 500k would be more warm/slightly bright. A 250k pot with a single coil will be more warm. A 250k on a humbucker will be more warm/muddy. A 1 Meg pot with a single coil would be very bright, and for a humbucker it would be just bright.
One other note is that while a higher number is more bright, it also rolls off the highs tones faster as you turn it down.

Now, when you go to choose your pots, you will see A500k, or B250k, etc.

What do pots actually do?
On the pot body there are 3 lugs to connect wires to. You know on a stereo there is a "Balance" knob, that fades the sound from left to right? It's kind of like that. Imagine the sound is coming in through the middle lug. With the knob turned all the way one way, all the sound goes to one of the outer lugs. With it turned the other way, it goes to the other lug. In between is just different levels of fading between the two.

- Volumes -
Now, what is actually happening when you turn the volume down?
When you turn the volume all the way up, virtually all of your sound signal is going to your amp (I say "virtually", for reasons discussed later). When you begin to turn the volume down, you are actually routing some of your signal to the ground of your circuit. The more you route to the ground, the less volume you have. So there are several ways to achieve this:

How are pots wired?
First, for volume pots, there are several ways to wire them. Whatever signal is going through the pot will be affected. If its coming from just one pickup, it will control just that pickup. If it is just before the output jack and has all pickups through it, it will be a master volume.

Left: Independent, Right: Dependent

Either way functions essentially the same. There is one case in which it DOES matter however.
If you are using individual volume controls for each pickup, instead of a master, you will want to use the diagram on the left, called INDEPENDENT. This puts the output on the end lug, not the middle.
This is because when the volume is turned down, the output is connected to nothing, instead of being grounded. If it were grounded, then everything connected to the output jack would be grounded, meaning if you were only using the bridge pickup, and the neck volume was all the way down, the output would be grounded and there would be no sound at all even if the bridge volume was up all the way!
As a note, the ground wire shown in brown goes to the back of the volume pot. Often times, you wont even need a wire, you can just bend the lug back and solder it to the back or side of the pot body.
What DOES matter is which side of the pot is the ground. To turn volume down, you turn the knob counterclockwise. Looking at the MS Paint picture above, you are looking at the pots from the bottom. This is how you want the ground. If it is moved to the other side, you will be turning the knob the wrong way to turn it up.

- Tones - Now, what's the deal with tone pots and capacitors?
A tone pot can be added like a volume pot, to whatever source you want to control.
Choosing a capacitor is all personal preference. The higher the number you choose, the more treble will roll off with the tone all the way down. With the tone all the way up, the number makes no difference. In my opinion, a higher number makes more sense. If you want tone control, why not have more variability? Common values are .047uF, .033uF, and .022uF.

So what happens when you turn the tone down?
Very much like a volume pot, a tone sends signal to the ground. But in this case, it sends it through the capacitor first. Think of it almost like a magnet that pulls high tones out. The more you turn the tone down, the more pull the magnet has and the more highs are lost.

Tone pots can be wired in many places in the circuit. Mainly all that changes is where the signal comes from, so the actual pot is wired the same. Here is how the pot is wired:

Pretty simple. Now, this is not an input with an output. Usually that red "in" wire will attach to either the "in" or "out" lug on the volume pot. So its kind of stealing the signal from the volume pot. When the tone is all the way up, the signal is routed to the empty lug, which does nothing, so no tone change. When you turn the tone down, more and more is routed through the capacitor.
You're now ready to move on to Basic Switch Wiring!

The Basics of Pot's | The Basics on Switch Wiring | Bringing the Switch and Pots Together | More Advanced Switching Options