Volume and tone controls are variable resistors, also known as potentiometers or “pots” for short. Volume and tone pots are the same component but a capacitor is soldered to the earth tag of the tone pot to prevent some treble from earthing out.
Inside the pot is a carbon strip which can get coated with dirt, causing the pot to produce a “scratching” sound when amplified. This can be improved by spraying the interior of the pot with switch cleaner and then rotating the pot to its extremes immediately after applying it.
Lin or Log?
There are two types of potentiometers within the electric guitar circuit: Linear or Logarithmic.
Without going into reams of electronic detail and terminology, it is sufficient to say that they behave in different ways when they are being adjusted.
Linear pots increase the volume or tone in an even and smooth way, whereas Log pots do so exponentially, increasing rapidly as the shaft is rotated.
In the guitar circuit 250K or 500K value pots are used.
(For more reading on this visit GuitarNuts.com)
Switches, such as 3-way Toggles or 3, 4 & 5 way Selector Switches become worn and can break down. While they are generally inexpensive to replace, the cheaper replacement components should be avoided, as they are of inferior quality and their durability is questionable.
Most often this is a problem on vintage instruments that have seen better days or those that have been incorrectly repaired. Loose wiring, dry solder joints, broken connections and burnt insulation can all cause problems. More…
Shielding can be done by painting the electronics cavity with Nickel Print shielding paint or lining it with special adhesive backed copper foil or heavy duty aluminum foil.