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Pickup overview

A magnetic pickup, such as those used on the Schecter Hellraiser guitars, consists of a permanent magnet such as a AlNiCo, wrapped with a coil of a few thousand turns of fine enameled copper wire. The pickup is mounted on the body of the instrument, underneath the strings. The vibration of the nearby soft-magnetic strings induces an alternating current through the coil of wire, and this signal is then carried to an amp via a cable.

Single Coil vs Double Coil "Humbucker" Pickups

A single coil pickup , like the above diagram, has a single winding of wire around a magnet or series of pole pieces which electromagnetically converts the vibration of the strings to an electric signal.  Simple and effective, single coil pickups defined the sound of guitar music from the late 1930s through the Classic Rock era and towards the end of the 20th century. attempts were being made however, starting in the 1970s, to address the single coil system's most undesirable side effect.Magnetic coils are very sensitive to interference, including 50kHz or mains hum.  This is undesirable because the hum pollutes the musical notes being played on the instrument with its own fixed frequence sound which is discordant with the desired musical sounds.

A double coil pickup or humbucker has two coils with opposing windings and polarities which are connected in series.This causes interference and noise such as mains hum to be cancelled.  Hence humbuckers get their name from the fact that they cancel out the interference (they "buck the hum") which is normally experienced with single coil pickups. In contrast though, the signal from the guitar strings from both coils in a humbucker is in-phase, so when the two sine wave signals meet, the amplitude of the wave doubles, and so does the signal strength from the guitar.This gives the humbuckers' characteristic "warm" and "fat" tone.

Early Humbuckers - Gibsons and Strats

A successful early humbucking pickup was the so-called PAF (literally "Patent Applied For") invented by Seth Lover, a Gibson employee, in 1955.The first guitar to use humbuckers in substantial production became the Gibson Les Paul.

Since then, humbuckers are factory fitted even in some of the guitars most traditionally associated with single-coil pickups, such as Fender Stratocasters and Telecasters. Because of the "fatter", "rounder" tone offered by the humbucking pickup, Stratocasters fitted with a humbucker in the bridge position, resulting in a pickup configuration noted as H-S-S (starting at bridge pickup: H for humbucker, S for single coil) are referred to as "Fat Strats".Fender Stratocasters with two humbuckers (H-H) are referred to as "Double Fat" Stratocasters, and those with the configuration H-S-H are commonly known as Superstrats.

Coil Splits

Some humbucking pickups feature coil splits, which allow the pickups to act as "pseudo-single" coils by either short-circuiting or bypassing one coil. The electrical circuit of the pickup is reduced to that of a true single coil while the magnetic circuit retains its original closed loop configuration. This feature is usually activated using a miniature toggle switch or a push-pull switch mounted on a potentiometer, hence the "push-pull pots" of modern EMG pickups such as the EMG 89, EMG 707-TW, and EMG 81-TW featured on guitars such as the Schecter Hellraiser C-1 FR.

The next Post will explore the difference between Passive and Active Pickups.