Patent ID: 7166793

Claim:
An improvement in stringed musical instrument hum-bucking electromagnetic pickups having a pickup coil surrounding a pickup core region containing a permanent magnet system linking strings of the instrument, and having a hum-bucking coil surrounding a hum-bucking core region disposed in co-linear alignment with the pickup core region and containing a magnetically permeable core-piece, the hum-bucking coil being interconnected in opposing polarity with the pickup coil so as to provide cancellation of unwanted hum interference as a tradeoff for an amount of tonal degradation due to audio circuit intrusion of the hum-bucking coil, the improvement comprising: a flux transfer structure of magnetically permeable material having a first portion surrounding at least a major portion of the pickup coil externally, and a second portion disposed internally within the hum-bucking coil in the core region therof, contacting and surrounding at least a major portion of the core-piece, the first and second portions being seamlessly and continuously interconnected by an intermediate offsetting portion so as to form overall a funnel shape such that a set of environmental hum and noise flux lines within a total extent of the first portion having a cross sectional area approximating that of the pickup coil are caused to become compressed and intensified into a much smaller cross-sectional area in the core region of the hum-bucking coil containing the core-piece, thus intensifying flux density in the hum-bucking core region in an unusually efficient and effective manner due to the seamless interconnection provided by the intermediate offsetting portion; and the hum-bucking coil having substantially fewer coil winding turns and thus able to made in smaller size than the pickup coil, due to effectiveness of said flux transfer structure, consequently providing a reduction in both overall pickup size and in the amount of amount of tonal degradation due to audio circuit intrusion of the hum-bucking coil.