rock, and British Invasion bands such as the Searchers, The Beatles and The Who. The early models were equipped with low-output toaster pickups. With the late-1960s advent of heavy rock, these were phased out circa 1969–70, and replaced by high-gain pickups with twice the output. Still, the early models were viewed by Pete Townshend as pivotal in his refinement of feedback techniques and the eventual development of the Marshall sound. In recent years, a diverse cross-section of artists have played Rickenbacker guitars. In 1979, Tom Petty and Mike Campbell of Tom Petty and the Heartbreakers used vintage 1960s models to attain that toaster-pickup jangle. The high-gain pickup sound is associated with acts such as The Jam and R.E.M. In 2014, Rickenbacker introduced the Walnut series: the 330W, 330W/12, 360W, 360W/12, and 4003W. These models have walnut bodies with a hand-rubbed oil finish, and unfinished maple fingerboards. Basses The 4000 series were the first Rickenbacker bass guitars, introduced in 1957. They followed the 4000 with the 4001 (in 1961), 4002 (limited edition bass introduced in 1977), 4008 (an eight-string model introduced in the mid-1970s), 4003 (in 1979, replacing the 4001 entirely in 1986 and still in production in 2021), and most recently the 4004 series. They also made the 4005, a hollow-bodied bass guitar (from 1965 to 1984)—which did not resemble other 4000 series basses, but rather the new style 360-370 guitars. The 4001S (introduced 1964) was basically a 4001 but with no binding and dot fingerboard inlays. It was exported to England as the RM1999. However, Paul McCartney received one of the early 4001S instruments (his unit was left-handed, and later modified to include a zero fret). Along with McCartney, other early adopters of the 4001 were Roger Waters (Pink Floyd), John Entwistle (The Who), Pete Quaife (The Kinks), Chris Squire of Yes and Geddy Lee of Rush. The model 4003S ("standard") arrived in 1985, was discontinued in 2000, and relaunched in 2015. This was similar to the 4001S with its dot neck markers and no binding. From 1985 to 2002, the 4003 and 4003S had black hardware and black binding options available. Later special editions included the 4003 Blue Boy, 4003 CS (Chris Squire), Blackstar, Shadow Bass, Tuxedo and 4003 Redneck. Rickenbacker basses have a distinctive tone. The 4001 and 4003 basses have neck-through construction. The 3000 series, made from the mid-1970s to mid-1980s, were cheaper instruments with bolt-on