With the introduction of the two-pickup 4001 model in 1961, the Rickenbacker bass became a phenomenon. The Beatles's use of Rickenbacker instruments was pivotal: teen groups everywhere wanted to have the same instruments the Beatles used so they could achieve the right sound. With its ultra-modern design that made the classic Fender precision bass look downright old-fashioned, the Rick quickly became a darling of progressive bands that loved its look as much as its different sound. The Rickenbac...