[yegbert]

The narrative from Duchossoir's book on page 62:

THE 70s HUMBUCKING PICKUP

The pickup found on the Deluxe and the second generation of Thinline and Custom models was designed by former Gibson engineer Seth Lover. His Fender brainchild features two coils, each wound with 5000 turns of 42 gauge wire and a resistance of 5300 Ohms +/- 400 Ohms (i.e. a nominal resistance of 10.6k for both coils together).

Whilst adopting the humbucker mode for Fender, Seth Lover was keen to retain a brighter sound and a higher resonant peak frequency than a Gibson pickup. Besides, the magnets were also to serve as direct adjustable pole pieces (cf the 1953 single coil "Alnico" pickup he designed for Gibson). To this end, Seth used a special alloy made of Copper-Nickel-Ferrite (=Cunife), which was then the only magnetic material likely to be machined and threaded. Cunife magnets also contributed to providing a concentrated flux field and keeping the inductance to a lower level (hence more trebles) than Alnico V, all else being equal.

The 70s Fender humbucker is fitted with 12 threaded magnets but, once the metal cover is soldered, only 6 - split in two offset rows - are fully adjustable in height from the top. It remained in production between 1971 and early 1981 and disappeared from the catalogue with the discontinuation of the Deluxe and Custom models.