The earliest Jennings Musical Industries Wah-Wah pedals: 1967 and early 1968

Over 2000 grey wah wah pedals were made at the Vox Works in Erith from around February/March 1967 to early 1968 - probably a 12 month period. Sales must have been good. Naturally we do not know in finite terms how many survive, but from those that do the changes that that took place in the course of production can be charted reasonably well. Some of the phases - the ntroduction of new types of component, for instance - overlap, others are more distinct. The examples below give an overview.

The page has benefitted hugely from the advice and findings of Stu Castledine. His website . Errors that remain are my own. Do let me know of new pedals, things to be corrected, and so on at this address.

There is a .

Vox retail pricelist, April 1967

"Beat Instrumental", vol. 48, April 1967, p. 24, the new effect connected explicity with the mid-range-boost of the new Vox solid state amplifiers. For further notices of Vox equipment in "Beat Instrumental", .

Beat Instrumental number 49. May 1967

Entry for the Vox Wah-Wah pedal in the Solid State brochure of Summer 1967. Note that this pedal, along with the one pictured above (probably the same), has a clear pre-production, or at least early production "Wah Wah" label on its side - no curved loop under the jack socket.

A brief account of the development of the Wah Wah pedal in the States - well covered in other sources - will be given here shortly - simply to give some background to the pedals issued by Jennings in 1967. In the meantime, see for instance, .

The advert above, from "Beat Instrumental Magazine", April 1967, is one of the earliest public indications of JMI's move to produce a pedal of its own. The retail pricelist will not have been widely circulated.

The first Jennings wah-wahs are often called "greys" - the colour of their casings. Serial numbers apparently began at 5000 and run on certainly to 6451 and doubtless beyond. Whether there was one pedal for every number in the sequence remains to be seen. But they were evidently produced in reasonable numbers. The rather bonkers claim that there were "only 100 made" probably stems from dealers or "gurus" bigging things up. These pedals are not prototypes, nor are they from 1966 as is sometimes said.

By the time we come to serial numbers in the 7500s - 7800s, we have a model of a different sort. The pedal externally looks like an American model, but the plate on the bottom has the symbol of the Queen's Award for Industry, the name of "Jennings Musical Industries", and lower down "Made in Italy for VOX". Serial numbers are printed on a paper sticker.


At first, the 4uf capacitor employed in the circuit was a yellow Lemco - also used extensively in the preamps of the new Vox solid state amplifiers. Visible date codes on the caps in the pedals are "YB" = February 1967, and "YF" = June 1967. Thereafter, or apparently thereafter, one finds green TCC (Telegraph Condenser Company) 4uf caps. Date codes are "YE" = May 1967, and "YF" = June '67. Later Lemcos were used again - date codes "YJ" and "YL" = September and November '67.

Transistors are at first BC150, then 2N3707. The date code on the majority of the 2N3707s is "716" which indicates the 16th week of 1967 = April 1967. We also have "743" = the 43rd week of the year = October 1967. Assembly of pedals with late '67 component codes is likely to have taken place early in 1968.

Component date codes are necessarily simply termini post quem - "dates after which". Weeks or months could elapse between the manufacture of the component and its being picked off the stockroom shelf at the Vox Works in Erith for incorporation in a unit.

Serial numbers are at first hand-stamped on the white traffolyte label on the underside of the pedal. Later they were stamped on the base plate. See no. 6012 below.

It may be that there were two sets of benchs in the workroom or workrooms - one that stopped putting on traffolyte plaques at around serial number 6000, another that continued to around number 6300 (highest so far 6273).

Number 6251 survives with its original box - entry here - a wonderful thing. Below, a growing register of pedals:


Yellow Lemco capacitors, BC150 transistors, glooped boards to prevent discovery of the circuit. White traffolyte plaques with stamped serial numbers on the underside.

The grey earth wiring on the pot and jacks, and the brown earth wires from the board are separated. Input wires are yellow; output white. The wire going to the pot wiper is green.

Serial number 5130

Known to exist - formerly in the USA, now in Russia. Thanks to Mike for the info.

Serial number 5351

Serial number 5527

Advertised currently. Further pictures. The component board has been glooped in rubber solution to prevent discovery of the circuit. The original BC150 transistors are present and correct.

Serial number unknown

The circuit board glooped, as above. The transistors, the tops marked with white dots of paint to indicated that they have been tested, are BC150.

Second format

Yellow Lemco capacitors (date codes "YB" to "YF"), 2N3707 transistors, untreated circuit boards. At first, white traffolyte plaques with stamped serial numbers on the underside.

The yellow and white jack wires remain, but now the input to the board is orange, output wires are grey, earth wires red, and the wiper wire blue (often a lighter blue earlier on). The brown earth wires are twisted together.

Serial number 5716

Serial number 5876

The 2N3707 transistor at board end has the date code "716" = April 1967.

Serial number 5879

The yellow Lemco 4uf capacitor has the date code "YF" = June 1967. The transistor at board end has been replaced.

Serial number 5964

2N3707 date codes are "716" = April 1967. The code on the Lemco capacitor is either "YE" or "YF" = May or June 1967. Two sets of pictures. The first three from the sale on ebay c. 2011, the others from .

Serial number 5985


Surfaced in Denmark, now in the UK. A good clean example. The transistors are "716" = April 1967, the yellow Lemco capacitor and pot "YF" = June 1967.

Serial number 6251

The star of the show - a pedal with its original box. Lemco capacitor code "YF", transistor code "716". Thanks to Raphael for the pictures.

Serial number 6258

The yellow Lemco capacitor has the date code "YB" = February 1967. Pictures .

Serial number 6273


White traffolyte plaque for the serial number.

Serial number 6330


Currently in France and advertised on Reverb (October 2018) - listing is here. Still the yellow Lemco capacitor, though no date is visible.

Third format

Green TCC capacitors, clear "Wah Wah" labels on the side, serial numbers aways stamped on the metal base plate. Wiring as the second format.

Serial number 5932

Serial number stamped on the base plate. Clear WAH_WAH stickers. Although the wiring follows the earlier colour scheme, transistor date codes are 716 and 743, which last is October 1967.

Serial number 6012

The transistor at board end has the date code "710" = 10th week (March) of 1967.

Serial number 6298

Serial number stamped on the metal base.

Serial number 6388

Serial number 6451

Note the date code on the green TCC capacitor: "YF" = June 1967.

Serial number unknown

Green TCC 4uf capacitor.

Serial number unknown

Green TCC 4uf capacitor. The 2N3707 transistor immediately above has the code TI 743 = which probably indicates the 43rd week (October) of 1967.

Latest format

Hardwired output cable. Back to Lemco capacitors (date codes "YJ" and "YL"), clear "Wah Wah" labels on the side, serial numbers stamped on the metal of the bottom plate.

Hardwired output cable and green earth wires. White and yellow wires occasionally on the input jack. Red sleeves on the buss wire from the 470K resistor.

Serial number 6847

The pot has the code "YL" = November 1967.

Serial number 6988

Lemco capacitor code "YJ" = September 1967. Output hardwired with jack plug on cable. Transistor date code "745". The pot has been replaced.

Serial number 7184


Pictures to follow soon.

Serial number unknown

Red sleeves on the solid buss wire. Not quite possible to see the date code of the Lemco capacitor. The transistor at end of board has the code "TI 743" or "745" - either 43rd or 45th week (October) of 1967. Some rewiring evident (and new jack sockets).

Serial number unknown

Red sleeves on the solid buss wire.


Note that one also finds a circuit board potted with resin in certain batches of Clyde McCoy "script" wahs (so-called to distinguish them from the pedals with an inset picture of Clyde McCoy) made in Italy for Thomas Organ, the company that owned, or at least laid claim to, the Vox name in the USA.

To date, Clyde "script" wahs with resin-potted boards have only turned up in Italy - ie. they seem not to have been shipped to the States. For more, .

In Italy, the pedals were distributed by Comusik, which handled the Vox solid state line, imported from England. The Comusik brochure is . The wah-wah pedal pictured on the Gyrotone and keyboard page is of the Thomas Organ rather than the English ("grey") type.

Wah nominally made for Thomas Organ but sold locally in Italy. Serial number 5992. No red inspection mark on the inductor. This pedal came from Rome.

Above, a Clyde McCoy "script" Wah made in Italy for Thomas Organ.

The Queen's Award version

Serial number 7857

The component board is "potted" with grey resin to prevent discovery of the circuit.

Serial number unknown - currently in the UK

Nothing altered. As above, the component board potted with grey resin. Potentiometer made by ICAR, wafer switch by Arrow (England). Thanks to Dave for the pictures.

Serial number unknown

Clearly different from the ones above. But only this photo for the time being.