Jennings Electronic Developments (JED) was formed by Tom Jennings, following his dismissal from Jennings Musical Industries (Vox) in 1967. The vast majority of the historical information on this page about Jennings and the Jennings fuzz comes courtesy of, which is by far the most authoritative resource about the history of Vox & Jennings musical equipment.

During the period of 1968 until the early 1970s, Jennings produced a series of distinctive guitar effects pedals with rotary foot-operated potentiometers, and these foot controls worked differently for each of the different models. The pedals were painted in grey Hammerite, and featured a plaque on the bottom plate, denoting the model name & serial number.

Jennings pedals
A selection of late 1960s/early 1970s Jennings pedals. (Photo credit: D. Johannson/API)

Among these different models was a Jennings ‘Repeater’ pedal, which produced a tremolo effect, with a variable speed control; a Jennings wah-wah pedal, where the resonant peak was adjusted via the rotary pot, as opposed to the conventional treadle format; and various Jennings boost pedals where foot-operated rotary volume controls. In the case of the Jennings Fuzz, the rotary foot control served to adjust the loudness of the fuzz effect.

In addition to a basic Jennings fuzz box, there was also the Jennings ‘Growler’, which was a combination of fuzz and wah-wah. Jennings also produced the ‘Scrambler’ (pictured below), which was a combination of fuzz, wah-wah as well as various boost options. The Practical Electronics magazine took interest in this highly esoteric model, and referred to it in the November 1969 & November 1972 issues. (Photo credit: D. Johannson/API)

Jennings Scrambler

The initial series of Jennings pedals was first reported being demonstrated at the British Musical Instrument Industries Trade Fair held in August 1968.1 The author of the report does not list the full range of Jennings effects that were at the show, but we can assume that the demonstration did include the Jennings Fuzz, because Jennings’ Growler (fuzz & wah) was reportedly present, and was also pictured in a promotional advertisement for the show.2

Pedals in the Jennings line were built with circuits similar to earlier Dick Denney designs. Dick Denney, himself, continued working with Tom Jennings during this period. Given the scale of production of all of the Jennings equipment, it’s unlikely that the individual pedals were assembled by Denney. However, at least one Jennings Growler (fuzz & wah) pedal that was modified by Denney is known to survive. The Growler in the photo below features a treble boost effect, in addition to the fuzz & wah circuits. (Photo credit:

Jennings Growler, modified by Dick Denney
Jennings Fuzz circuit board
The circuit board for the fuzz effect, used in the various different Jennings pedals, featured a pair of silicon transistors. This electronic circuit was similar to the silicon-transistor Vox Distortion Boosters.

For a brief period, starting in November 1968, the line of Jennings pedals was being distributed by the Rotosound strings company.3 Only one example of a Rotosound-branded Jennings pedal is known to have survived, and it is identical to the more familiar Jennings Fuzz, apart from bearing a different brand name.

Jennings pedals were also briefly sold by Framus (a German instrument manufacturer), as exemplified by a number of gold painted Framus Growler (fuzz & wah) pedals that have resurfaced. (Photo credit: B. Provoost/Effects Database)

Jennings Framus Growler

In 1969, Jennings Electronic Developments (JED) became known as Jennings Electronic Industries (JEI). Tom Jennings placed regular advertisements for Jennings equipment in Beat Instrumental, and the advertisements placed in 1969 suggest that the name change could have taken place between July and September of that year. The more precise date is unknown.

Bottom plates of JED & JEI Fuzz pedals

Following the name change, the branding on the bottom plates of Jennings pedals was adjusted accordingly. Pictured above is an example of the bottom plate from an earlier ‘JED’ fuzz, compared with a later ‘JEI’ fuzz. (Photo credit: C. Nelson & Y. Asai)

A suggested retail price list, dated December 1972, confirms that the Jennings ‘rotary foot control’ pedals were still in production into the 1970s, but the price list also makes reference to a newer series of ‘pedal foot control’ pedals. According to the December price list, the Jennings fuzz and Jennings wah-wah models were offered in both ‘rotary’ and in ‘pedal’ options, at the same price.

The Jennings Electronic Industries ‘pedal foot control’ units were built with the conventional ‘treadle’ enclosure, as had previously been used by many manufacturers around the world (including JMI) for volume control and for wah-wah effects. The JEI ‘pedal foot control’ series comprised a volume pedal, a wah-wah pedal, and also a fuzz pedal. Instead of the grey (and occasionally gold) colour schemes on the rotary pedals, this new series of Jennings effects were painted in a copper Hammerite finish.

Jennings 'pedal foot control' Fuzz
The Jennings ‘pedal foot control’ series Fuzz.

The Jennings effects pedals with the rotary foot-operated potentiometer had been in production since 1968, and were advertised regularly, but the ‘rotary’ series was eventually absent from the JEI catalogue & price list of 1973. The three newer JEI pedals with the treadle controls were, however, still pictured and listed, and apparently this pedal (or ‘treadle’) series replaced the ‘rotary’ series.

The JEI treadle-style pedals were, however, probably only built for an extremely limited period. Of the three different ‘pedal foot control’ models, only a single exemplar of one model of the series is known to survive. The JEI ‘pedal control’ Fuzz, pictured above, features identical circuitry to the ‘rotary control’ Fuzz, and functions in exactly the same way, other than that the volume of the fuzz is controlled by the treadle, rather than by a rotary potentiometer.

  1. Beat Instrumental, October 1968, p. 25
  3. Beat Instrumental, January 1969, p. 29

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