Electric guitars use
coils (guitarists call them pickups or elements) to convert the
vibrations of the strings into an electrical signal. Usually, a guitar
has more than one element builtin, so that the musician can select with a
switch which element or elements are used to generate the signal.
Because of the differences in construction of the elements and the
varying positions of where they are mounted, each element sounds
different. The elements can be roughly divided into two categories.
There are the so-called ‘single-coils’ and ‘humbuckers’. Single coil
elements are elements that contain one core and coil for each string.
Humbuckers can be regarded as two elements that are connected in series.
Many humbuckers have four connections (actually two single-coils with
two connections each).
These two individual coils are usually interconnected with ﬁxed
wiring so that they are always used in series. The circuit proposed here
offers the possibility of using a hum-bucker with four connections in
no less than four different modes, each of which having its own sound.
The only things that have to be changed on the guitar are the wiring and
the addition of a four-position switch. The latter requires drilling
holes in the guitar of course, but if there is a control cover plate
(along the lines of a Fender Stratocaster, for example) then it makes
sense to put the switch there. This avoids the need for drilling holes
in the wood while keeping an (expensive) guitar reasonably unmarred. The
schematic shows what the various things look like, electrically
speaking, before and after the multisound modification.