The Jazz Bass (or J Bass) is the second model of electric bass created by Leo Fender. It is distinct from the Precision Bass in that its tone is brighter and richer in the midrange and treble with less emphasis on the fundamental harmonic. It has a naturally more focused tone than the Precision Bass, with less low end and low midrange. Because of these tonal characteristics, the Jazz Bass is often preferred by bass players who seek a more noticeable sound, rather than serving as a background instrument. The sound of the Jazz Bass has been fundamental in the development of signature sounds in certain musical genres, such as funk, disco, reggae, blues, progressive rock, heavy metal and jazz fusion.
First introduced in 1960 as the Deluxe Model, it was marketed as a stablemate to the Jazzmaster guitar which was also marketed as a Deluxe Model in its own right. It was renamed the Jazz Bass as Fender felt that its redesigned neck—narrower and more rounded than that of the Precision Bass—would appeal more to jazz musicians.
The Jazz Bass has two single coil pickups with two pole pieces per string. This gave the bass a stronger treble sound to compete with the Rickenbacker bass, which had been introduced in 1957 and was famously "bright". As well as having a slightly different, less symmetrical and more contoured body shape (known in Fender advertising as the "Offset Waist Contour" body), the Jazz Bass neck is noticeably narrower at the nut than that of the Fender Precision Bass. While the Precision Bass was originally styled similarly to the Telecaster guitar, the Jazz Bass' styling was inspired by the Jazzmaster guitar, with which the Jazz shared its offset body and sculpted edges that differentiate it from other slab-style bass bodies.
The original intention of the instrument was to appeal to upright bass players. The original Jazz Bass had two stacked knob pots with volume and tone control for each pickup. Original instruments with this stacked configuration are highly valued in today's vintage guitar market. Around 1961 it received three control knobs: two controlling the volume of each pickup and one the overall tone. Despite this new feature, many stacked knob models were made until about 1962. Another feature the initial models had were the "Spring Felt Mutes", which were present on basses from 1960 until 1962. The purpose of those mutes was to dampen the overtones and the sustain, and were screwed in place between the bridge and aft pickup. Those felt mutes weren't a tremendous success, and were replaced by a cheaper, more simple foam mute glued underneath the bridge cover as was used by the Precision Bass from 1963 onwards. Over the following years as the use of mutes gradually declined both the Precision and Jazz Bass models eventually began to be produced without bridge/tailpiece covers.
A number of cosmetic changes were made to the instrument when CBS purchased the Fender companies in 1965. During 1965/66 the Jazz Bass received bound rosewood fingerboards with pearloid dot position inlays (which replaced the older "clay"-style of the early 1960s) and oval-shaped tuning machines. Block-shaped fingerboard inlays and an optional maple fingerboard were introduced after 1966/67. At first necks with rosewood fretboards received pearloid blocks/binding and maple fretboard necks received black. Fender switched to pearloid blocks/binding on all necks in mid-to-late 1974. Fender also switched to the three-bolt neck "micro-tilt adjustable" neck and the "bullet" truss rod in mid-to-late 1975 before reverting to the more standard four-bolt neck fixing and dot-shaped fretboard markers in 1983. White pickup covers and a pickguard/control plate were introduced the same year. In 1986 Fender introduced the Japanese-made Fender Performer Bass, also with micro-tilt neck, designed by John Page and intended to be an Elite version of the Jazz Bass, however the radical styling was not popular and production ceased the same year.
American Standard Jazz Basses produced between 1989 and 19941⁄2 featured a larger body shape, a 'curved' neck plate set into a chambered pocket for greater sustain and a 22-fret neck, similar to that of a Precision Bass Plus, with a standard vintage-style top-load bridge, two separate volumes and a master TBX tone circuit. Usually known as "Boner" Jazz Basses, these early American Standard models (designed by George Blanda, who was Fender's senior R&D engineer during that period) were discontinued in 1994 and shouldn't be confused with the Fender Jazz Bass Plus, which has the same 22-fret neck design, but utilizes a different (downsized) body styling, Lace Sensor pickups, Schaller "Elite" fine-tuner bridge on the four-string model or Gotoh high-mass bridge on the 5-string model, and Phil Kubicki-designed active electronics. Unlike the Fender Precision Bass Plus, which had a "maple-neck" option, the Boner Jazz Bass was offered only with a rosewood fingerboard. The Jazz Plus Bass was available with an alder body and the option of a natural-finish ash body on the four-string model for a $100 upcharge, either a maple or rosewood fretboard on the four-string and pau ferro (an exotic hardwood whose tone is brighter than rosewood yet warmer than ebony) on the five-string. The Jazz Plus debuted in 1989 (the five-string model was released in 1990), discontinued in 1994 and replaced by the USA Deluxe Series Jazz Bass the following year.