Electromagnetic musical pickup having U-shaped ferromagnetic core

Abstract

An electromagnetic pickup for a musical instrument, such as a guitar, strung with ferromagnetic strings, comprises an elongated ferromagnetic (steel) core of U-shaped or double U-shaped transverse cross-section. An electrical pickup coil in a non-magnetic coil form encompasses one core leg; transversely magnetized main permanent magnets engage the top edges of the core legs. The magnets, which may be integral with each other, are preferably formed of a resin impregnated with magnetic particles; they maintain adjacent core legs at opposed polarities. The main magnets may be mounted in or on the top of a housing that encloses the core and the coil; the housing provides for mounting the pickup in spaced relation below the strings so that the pickup produces a magnetic field that encompasses the strings and string movement generates electrical signals in the coil. There may be additional permanent magnets to shield the coil. Dual-coil humbucker embodiments of the pickup are described. Frequency response, "sustain", signal-to-noise, and amplitude characteristics of the pickup are varied by selection of thickness and material of core members, by the shield magnets, by the size of wire used in the coil, and by the compositions and magnetization patterns of the main permanent magnets.