After Leo Fender introduced the Precision Bass in 1951, other instrument makers saw the potential of the electric bass guitar and jumped into the market. Gibson introduced its Electric Bass (later known as the EB-1); Danelectro rolled out its Short Horn and Long Horn models; and, in 1957, Rickenbacker offered its Model 4000, the first neck-through-body bass. By the time Paul McCartney arrived in the U.S. in 1964 with his Hofner 500/1, there were many different electric basses available. One popular model in the late ’60s was the Guild Starfire Bass, a semi-hollow 4-string available in one- and two-pickup versions. It became the preferred bass of two notable San Francisco musicians, Phil Lesh of the Grateful Dead and Jack Casady of the Jefferson Airplane. Both liked the sound of the Hagstrom Bi-Sonic pickups but felt the stock electronics left something to be desired. Modifications were in order, and they turned to a group of technical wizards in the Bay Area. The mastermind of the op