Vox AC30 website updates
May 2021
31st May (2)
The "standard" advert for the "Cliff Richard" Echo (Reverb) first appeared in "Melody Maker", 19th May, 1962. It was also printed and circulated as a promotional flyer.
Two JMI circuit diagrams survive for this unit: A62-005, dated 30th January 1962; and OS/011. The reverb circuit integrated in the AC30 SRT from Spring 1962 should probably be regarded as being a spin-off - there are as one might expect some points of contact, but the requirements of the standalone unit were naturally very different.
31st May
An early Treble chassis made by Burndept, chassis number 3098, tremolo and vibrato circuitry later removed. The two blue Hunts 25uf capacitors have date codes "TWI" = 41st week of 1963; the main preamp filter has "TDI" = 48th week of '63.
30th May
A quick shot of the first of a series of ads for the new Vox Echo - really simply a reverb unit - "Melody Maker" magazine, 14th April, 1962, i.e. less than a year after the ad for the Italian made Meazzi Echomatic version 2, a true echo machine, based on a drum system. Whether Alan Larkins of the JMI Research and Development Dept. had anything to do with the electronic design of the new Vox "Echo" is not known. 1962 may be a little early. He certainly played a large part later on with the "Tom" echo units.
Further material relating to echo and reverb units coming shortly.
29th May
Below, a picture of the Goodmans Axiom Works in Wembley, published in the High Fidelity Loudspeaker Manual of 1960; and one side of a flyer advertising the Audiom range, c. 1959. The suggested uses are fewer in number than those proposed in 1953 probably due to the constraints of space - see the advert for instance on this page.
28th May
Thanks to Pat, pictures of the tag accompanying AC30 serial number 9834B (pictures of the amp to come). These tags are likely to have been designed in 1961, perhaps at much the same time as the promotional booklet with the green cover for the AC30/6. Illustrated: a Celestion blue, and an AC30/6 control panel with white knobs. presumably simply for clarity.
26th May
From around chassis number 3000, Burndept indicated the "voicing" of the chassis it produced for JMI not only with a stamp in red, but a colour code. "TREBLE" had a red splash; "T/B BOOST" (integrated treble and bass controls on panel) had green; and "BASS" - produced in smaller numbers - had blue. "Normal" AC30s had neither stamp nor colour.
The splash of colour was presumably supplied - while the chassis was on the assembly benches - to indicate how the voicing should be stamped above it.
Detail of serial number 11613T, chassis number 3083.
Serial number in the 12000s, chassis number 4530.
Serial number in the 18000s, chassis number 8407.
23rd May
Jennings, it turns out, will have known about Geloso connectors well before 1961. Below, an advert in "Melody Maker", 19th September, 1959, for the first version of the Meazzi Echomatic carried by JMI - known as the "Echomatic 1" or "Model J". Also, a picture of a surviving unit, with bronze "Jennings" label on top at front, from this page.
It seems unlikely that Jennings was ordering batches of connectors at this point (1959) though. The Meazzis will have come from Italy fully assembled.
A set of new pages on Vox Echos and their users - hardly just "Cliff Richard" and "The Shadows" - will available in due course.
A wonderful Meazzi Echomatic Model J with "Jennings" label - picture from this page.
22nd May
The page on Geloso sockets and connectors, fitted to certain AC30 Super Twins, is currently building. An early securely dateable instance of their use is the Vox Meazzi Echo, advertised on 11th March, 1961, in "Melody Maker" magazine.
"Melody Maker" magazine, 11th March, 1961.
21st May
Thanks to Laura, a substantial amount of information is now available on the Jennings "Model G" organ installed in the Civic Auditorium in Lower Hutt, New Zealand, in early 1958.
In brief: - an opening recital for the Wellington Association of Organists took place in June 1960. Various evenings of organ music followed. In 1965 a local firm - the Howell Piano Company - was contracted to service the organ. Unfortunately by the time a number of significant faults had developed a couple of years later - principally relating to tuning and the failure of certain key contacts - Howell had gone out of business The town clerk sent to England for technical information on behalf of a new repairman, and Jennings forwarded a large set of service sheets (which still survive) to help with the fixing of the faults. Having been extensively rebuilt in the 1970s, the organ remained in regular use until 1983, when it was superceded by a modern replacement. It was sold in 1985.
20th May
Below, one of two adverts placed by Jennings in "Musical Times" magazine in 1958 presenting the Model C as an "asset to musical education". Both have been added to this page.
In another advert "HMS Victory" is given as the "Chapel of HMS Victory" - either the Dockyard Chapel (rather than a chapel on board the ship), or possibly the chapel of the old Naval Training College, which would in some ways make better sense in relation to the nature of the advert below.
"Musical Times", May 1958. A short list of installations in educational establishments.
18th May
Some details coming soon on Jennings Organs in 1960 - i.e. moving further into the "guitar and amplifier era". By December the Model G was over £2000 (1950 guineas), which would buy around twenty TV Front AC30 twins.
Below, details from the catalogue of the "British Industries Fair", London shows, 1956. Jennings not only exhibited the "old" line - the "B-series" - the J50, J51 and J52, but at least one example of the new "V-series". Slightly incongruously, the main theme of the 1956 London exhibitions was childrens' toys. Jennings came under the heading of "General" business, along with Barclays Bank, Keith Prowse and Co. Ltd, and the Linguaphone Institute.
This may have been the last "British Industries Fair" that Jennings attended.
15th May
Thanks to Andy, pictures of serial number 11715, chassis assembled by Burndept, inspection tag still in place in the preamp.
14th May (2)
Thanks to Shaun, pictures of serial number 12242B, superb condition, Celestion blues with date codes 18th and 20th February 1964.
14th May
Thanks to Andy, pictures of serial number 6664N, early-ish 1963. The Woden choke and mains transformer have the date code "HT" = August 1962 - in terms of serial numbers, a relatively late instance, as Wodens with November 1962 codes had certainly been supplied by the 6200s. The first definitively known instance of Wodens with "AU" codes (January 1963) occurs in the 6900s.
The control panel is of the newer type (1963) with "JMI" in relatively fat letters. Speakers are now Celestion silvers (T1088s).
12th May
A short note on the Hunts capacitors used in AC30s with reference to the company's pricelist of 1963. Notes on the date codes can be found here.
PREAMP
25uf/25v - Hunts code MEW29T - price 2s/6d.
8uf + 8uf/450v - Hunts code KDQ558 (also KNQ558 and KB558) - price 7s/6d.
POWER SECTION
250uf/25v - Hunts code MEF35T - price 4s/6d.
32uf/450v - Hunts code JFQ407T - price 6s/0d.
16uf + 16uf/500v - Hunts code KBQ562 - price 9s/6d.
It is likely that preferential rates (some measure of discount) were obtainable for bulk orders.
10th May
Further pics of an early Burndept chassis - chassis number 01028. Two of the black-print WIMA Tropyfols have codes "P1" and "P3". The cabinets are likely to be reproductions. Westrex rather than Burndept chassis are normal in Super Twin amps.
The amp's serial number is likely to have been in the mid or high 5000s. In terms of amps that have so far come to light, AC30 serial number 5619 is the first to have been fitted with a Burndept chassis.
8th May
The sections on Jennings Organs continues to grow. Below, one of the items recently added - from "Musical Opinion" magazine, December, 1959 - the "Model G" organ with an output totalling 150 watts - three of Derek Underdown's 50 watt power sections as "separate channels". JMI's most powerful guitar amplifier at this point was the AC/30, capable of running 20-25 watts into its single Goodmans speaker. The single speaker was the limiting factor.
"Musical Opinion" magazine, December, 1959. Model G.
5th May
"Musical Opinion" magazine, November 1956 - the Electro-Bass and a hitherto unknown amplifier: the Jennings E.B.1.
There were therefore at least five Jennings amplifiers prior to the AC2/30 of 1957:
1952: - the single speaker Univox amplifier (not to be confused with the portable organ), 15 watts, 16" x 11" x 12.5".
1954: - single speaker, bow front, rectangular speaker opening, 5 inputs, 15-25 watts.
1955: - single speaker, initially released to accompany the J48 organ.
1955-1956: - single speaker G1/10, probably developed from the J48 organ amp.
1956: - the E.B.1, single speaker, 12 watts, 3 inputs, 24" x 20" x 11", presumably designed to accompany the Electro-Bass - E.B.
"Musical Opinion" magazine, November 1956.
4th May
Recently on Reverb in the States, some of serial number 5955N. The cabinet is later. The chassis, which has Haddon transformers, is probably from 5955, along with the upper section of fawn/beige backboard (corners roughly rounded) and its serial number plate.
3rd May
Currently on Reverb, AC30TB serial number 2749, assembled in Italy in 1968 - some good pictures of the perforated tag board and components. Perhaps the most interesting thing is the sticker inside the cabinet apparently dated in Italian handwriting: 16-3-68. JMI was still in business in March. The "3" certainly does not look like a malformed "8". The page on Italian-made AC30s has provisionally been revised. Further updates will be necessary.
1st May (3)
Thanks to David, a pic of Super Twin serial number 3660 with an earlier speaker cabinet, the two long paired. The Celestion blues have February 1964 date codes. The amp is one of the last of the early 1965 amps to have a rectangular cabinet. Soon after, the new slope-side cabs came in.
Serial number 3660 - currently in the UK
1st May (2)
A synopsis of the models of organ produced by the Jennings Organ Company, 1954-1959, with known dates, is now avaliable here. Some of these dates and details may need to be revised as new information comes to hand, so do check back from time to time.
1st May
The page on Jennings Organs, 1958 is now up. A companion page will probably join it next week - information relating to one of the installations mentioned is likely to come in. Pages for the other years currently online have been updated. In progress, an overview of the models and date of introduction.
It is interesting to find a parallel for the "futuristic" design of the "J51", introduced in 1954 and later redesignated the "Model D2" - see the image below, entry for the 28th April - in the Compton Melotone. Image from this page.
Updates for October and November 2020.