9th November

Entries for four more early AC4s have been added to this page - serial numbers 2485, 2615, 2699, and 2969. Select pictures to follow. One of the hallmarks of these amps as they come to light over 60 years now after manufacture is their superb condition.

8th November

Thanks to Colin, pictures of AC15 serial number 4641B have been added on this page.

7th November

Thanks to Magne, a page has been added on AC30 Super Reverb Twin serial number 8067N, third quarter of 1963, exported to Norway early on.

The designation "SRT" was not stamped on early serial number plates primarily, one suspects, because the shorter info panels simply had no room for it. Only when plates with wider panels came in was "SRT" included.

AC30 SRT serial number 8067N.

5th November

There is now a page on AC30 Super Twin serial number 7785N. Thanks to Phil for the pictures and info.

AC30 SRT serial number 7785N.

3rd November

Thanks to James, pictures of AC30 Twin serial number 5441N, late spring/early summer 1962, in superb condition, have been added here.

AC30 serial number 5441N

1st November

Thanks to Frédéric, pictures of AC30 Twin serial number 8857N, third quarter of 1963, have been added here.

AC30 serial number 8857N.

30th October

Thanks to Steve, pictures of AC30 Twin serial number 15210T, third quarter of 1964, now nicely refurbed, have been added here.

AC30 serial number 15210T

29th October

Thanks to Phil, some pictures coming of AC30 Super Reverb Twin serial number 7785, one of the earliest SRTs currently known, speakers dated July 1963.

AC30 SRT serial number 7785. The corner protectors with double pins are not original. An early instance of basketweave vinyl or re-covered?

28th October

November 1964, a detail from a rough-print picture of the John Barry Seven. The Continental is from later 1963, tall lid (so-called "square lid"), a music stand perhaps flat on its top. On the back panel, a "VOX" logo in cursive (not "Vox Continental"); and an inset aluminium panel for the mains and speaker sockets.

A page on bands with early Continentals can be found here.

Published November 1964. The T60 bass cabinet, with a Super Twin amplifier section on top, is probably a little earlier than the organ. Its perspex logo can just be made out.

27th October

A screen-grab from a film on Jennings shown on British TV (Southern Region) in late August 1964, Doug Daniel pretending to test a Vox Continental for the camera at 115 Dartford Road, the amplifier and speaker at right a T60 bass set-up.

Doug can be seen in the background of the picture posted on 22nd September, further down this page.

One of the testing booths in 115 Dartford Road.

A detail of the lintel of Doug's booth taken from another photo. Someone wrote his name to the left of the door, and (helpfully) "Doug's Booth" above. "X" from a Vox logo marks the spot.

26th October

A screen-grab from a short film on Jennings shown on British TV in early 1965 - a sheaf of the Thomas Organ Company's purchase orders (addressed to Cyril Windiate, Tom's deputy). The page in view, dated 30th January '65 and part of the second large order placed by Thomas, concerns guitars.

Warwick Electronics Incorporated owned Thomas and its parent company Pacific Mercury (Thomas and Pacific both presided over by Joe Benaron).

The first order for equipment placed by Thomas - "The Million Dollar Deal" - was announced in late August 1964, having been formulated earlier in the summer. JMI accelerated production in advance of the announcement. More on exports to the USA can be found on the Vox AC100 website.

Early 1965.

25th October

Published in June 1965 though taken some months earlier, a shot of the JMI guitar work-benches, a new-style AC10 Super Reverb Twin amplifier section in view, its speaker cabinet doubtless close by.

June 1965.

24th October

In relation to the note on 22nd October, true, the ranges of amps mentioned all have logos of single letters, their sides painted (hand-painted) in red. However, they are generally of a different type from the "V" and "O" illustrated - pressed cardboard with a silver foil overlay.

The letters in view (as the main point of the entry) are made of plastic/acrylic of the early type, base colour yellowy-orange (more vivid than 1960s logos), and with the silver coating likely to have been vacuum applied.

As for the "form", one can see in the shot of the backs that the thicker arm of the "V" is not regular as it approaches the intersection with the other, perhaps indicating the letters were cut away from an early single-piece logo - i.e. a logo with a bar joining the letters and three mounting posts at back (for fixing on the cabinet front).

On the other hand, the mounting post of the "V", where bar logos are concerned, sits partly on the bar and partly on the letter itself. Close inspection shows that a mounting post is unlikely to have been present.

Possibly a short-lived transitional form from late 1959 / early 1960? More to come on logos shortly.

22nd October

23rd October: - the comments below are incorrect, thanks to Glen Lambert for pointing out. A corrected note to be provided shortly.

Probably from an early AC/15 (first circuit), i.e. one of the first 250 amps made, two letters from the logo, 1 1/4" tall. It is possible at a pinch that they came from an early single-speaker AC/30 or AC/10, but far fewer of these amps were given such logos - perhaps as few as thirty AC/30s and ninety AC/10s.

Letters were glued onto the grille cloth with contact adhesive (cement).

Detail of the logo of AC/15 serial number 3582, foil lost in parts. The diamonds of the grille cloth are 2" tall.

21st October

American music trade press, September 1960, one of the first adverts for the new Hammond reverb assembly, pitched initially at hi-fi and radio manufacturers. Makers of guitar amplifiers did not bring out models with integrated reverb until well into 1961. In terms of advertising, the order of adopters was: Supro (April 1961); and Gibson and Ampeg (May 1961). The first Fender unit was the stand-alone single-input 6G15 (July 1961), aimed principally at guitarists and accordionists.

A few months later, in November 1961, Fenton Weill followed Supro's lead, bringing out a unit equipped with a speaker to enable vocalists or guitarists (both mentioned in the advertising, inputs designated on the control panel) to use the box on its own, or as a sort of preamp for another amplifier - this last, much as Fender's G615. The design does not seem to have been a great success.

Jennings, in contrast, aimed its stand-alone reverb unit - endorsed by Cliff Richard - squarely at vocalists early on (i.e. in 1962). In many ways, a much better idea. Two channels, specific type of use undesignated, were provided, each with its own volume control and identical gain structure.

Detail of a Jennings reverb unit from 1963.

September 1960.

20th October

Some new entries on the page on Dallas-made AC30s, 1974-1975. It may be necessary to put the two years on pages of their own at some point. Pictures of serial number 2296 (from late 1975) thanks to Colin.

That Dallas serial numbers were *always* added at the point at which amps were fully ready for sale - chassis, cabinets, speakers, cover, documentation, all in place - seems unlikely. Number 2189, for instance, has an October 1975 plate and an original T1088 dated 30th October (for its manufacture by Celestion in Ipswich). Was there really only a day between the speaker's manufacture and its installation in the cabinet?

19th October

Christmas approaching, 1962, a short run of "Musicland" ads. On the 15th, a Fenton-Weill reverb for £25, the first stand-alone unit to have been produced by a British manufacturer (advertised in November 1961).

Christmas 1962.

18th October (3)

Below, a detail of a Supro catalogue said to be from 1961 (if so, late). Just visible is the line at foot "Licensed under Hammond Organ Co. patents".

Supro catalogue.

The main patent that Hammond took out for its tank - not (generically) every and any reverb tank - is US3106610, granted in October 1963, applied for in January 1961.

Hammond patents for the USA, Canada, Belgium, France, Italy, and Japan.

Those at JMI will probably have seen the "patent applied for" stickers on Fender reverb equipment, still distributed in the UK by Jennings in 1961 and early 1962. The brief line devoted to reverb in the "Vox Story" - noted two entries down on this page - must be correct.

A page from the Hammond patent.

18th October (2)

The upshot of the situation regarding reverb, outlined in the previous entry, is:

1: - from early 1961 in the U.S.A., later in Europe, ready-made reverb tanks were available from Hammond. If they were to be resold as an integral part of an amplifier or stand-alone unit, then a license had to be purchased. Supro, for instance, made its possession of a Hammond license clear in its brochures. Nothing was said on the amps themselves though.

2: - manufacturers, conversely, were entirely free to design their own spring reverb system - circuit, tanks, implementation, and so - and install and sell it as they saw fit. The JMI "Cliff Richard" Echo was there for all to see. Hammond had no patent (in the strictest sense) on reverb tanks with transducers and springs in 1962 ["in 1962" added - a new entry forthcoming].

3: - too often the question of whether an implementation is "good" or "bad" is thrown off track by what we know today. Spring reverb systems are fragile, the chief point of failure in any amp that carried it. It was not such a good idea in the long term - prone to noise, erratic operation, complete unusability, etc. That some reverbs are easier to repair than others *nowadays* is just one of those things.

18th October

On page 61 of "The Vox Story" (1993) one of the many obiter dicta of Dick Denney is apparently summarised: that the system of reverberation implemented by JMI was effectively the one "invented by Hammond for their organs [in the late 1950s and early 1960s] and changed sufficiently by Vox to escape the patent", the underlying feeling being that JMI had worked to devise a means (a) of keeping costs down and (b) retaining independence from an all-too-distant supplier.

Jennings was not the only company to have done this. Certain organ manufacturers trod a similar path, as did the amplifier makers Danelectro (Silvertone) and Premier, among others in the USA.

The majority of British amplifier makers, conversely, appear to have hitched their respective wagons to Hammond - see the entry below for 15th October. So far as one can judge, sales of the new models with reverb were lukewarm; either that or the amps were ill-fated in some way. Selmer stretched the concept to its limits by adding reverb to its Clavioline in the autumn of '62.

Below, a provisional list of the patents held by Hammond (by date of approval/publication):

US2949805A: 23rd August 1960 - "Artificial Reverberation Control Apparatus", two amplifiers, one for the dry signal, one for the reverb, the level of the dry signal controlled by a volume (expression) pedal. Perhaps only really useful in a recording studio or small room.

US2967447A: 10th January 1961 - "Apparatus for translating musical tone signals into sound", a three-stage circuit: (i) a pre-amplified dry signal (from an organ, etc.) is passed to a dedicated speaker; (ii) at the same time the signal is directed to a spring system, the output from which (iii) is passed to an amplifier with a speaker of its own (ie. one speaker for the dry signal, one for the amplified signal with reverb). The driver transducer of the spring reverb network is electro-magnetic (coils and magnet), the pick-up transducer crystal (piezo).

US29892819A: 2nd May 1961 - "Artificial Reverberation Control Apparatus", a system of parallel springs, compact in nature, arranged in a sort of "necklace" (for use in an organ). Transducers are coil and magnet. A preamplified dry signal with its own speaker is envisaged.

US3037414A: 5th June 1962 - "Artificial Reverberation Control Apparatus", a revision of US2949805A, controlling reverb volume with a lamp limiter.

GB912720A: - 5th June 1962 - apparently the only patent expressly held by Hammond in the UK. Effectively the same as US3037414A - controlling reverb volume with a lamp limiter.

Whether the Hammond system was indeed "changed sufficiently by Vox to escape the patent" is unclear at present. The patent for magnet and coil transducers - rejected by Jennings in favour of piezo/crystal pickups - belonged to Bell Labs (1932).

It may be that the question hinges on what is meant by "patent". In the UK there are three main classes of legal protection. A patent for the most part covers mechanisms, whether purely mechanical or electro-mechanical. A "Registered Design" covers real world implementations (a reverb tray of a particular format or appearance for instance); and a "Trade Mark" covers the product's name or emblem.

At any rate this is probably an overly long way of saying that Jennings designed its own reverb and did not take out a Hammond license.

17th October

A neat box of transistorised tricks, July 1959. A slightly different selection was advertised in December. Although the "REVERBERATION" is unlikely to have had any bearing on later developments (it was presumably a sort of sustain or echo circuit), it would be interesting nonetheless to know even on a very basic level how the assembly was arranged.

July 1959. Some of the effects perhaps the precursors of those incorporated in the Vox Guitar Organ.

16th October

In contrast to the great fanfares produced by Fenton-Weill and others for their new amplifiers with built-in reverb, Jennings initially seems to have done very little to introduce its AC30 SRT to the public. Perhaps somewhere there are (illustrated) flyers and so on, but all we have at the moment are entries in pricelists, the first dated instance being 12th May, 1962 (detail at the head of this page). Focus from the outset was squarely on the "Cliff Richard" stand-alone unit, advertised in the mainstream music press from April 1962.

The earliest dated advert for the "Echo-Reverberation" unit currently known, early April 1962.

That the development of the circuit and hardware (spring tank and cartridge transducers) took place towards the end of 1961 is clear from OS/011, the main diagram, which is dated 30th January, 1962. Given the date of the promotional campaign, it evidently took some time to bring the unit to market.

Whether the AC30 Super Reverb Twin really holds a sort of secondary position in all this is not wholly certain at the moment though. The arrangement of the cabinet for the amplifier section of the "plain" Super Twin - with space beneath a slider board (as a fundamental part of the design) - was certainly a mighty stroke of luck if so.

The tray containing the spring reverb assembly beneath the slider board of an immaculate AC30 SRT, serial number in the low 8000s.

There is also the matter of the "Vox Echo-Reverberation" standee on top of the amp - Super Reverb Twin? - in the picture below (mentioned earlier this year, entry for 25th July). The portrait of the star at left certainly does not match any known photograph of Cliff Richard used by JMI. Is it Cliff?

Original photo owned by Andy Babiuck. The standee is approximately 2 feet long and 7-8 inches high.

A further fairly obvious question: why no production Twin - AC10, AC15, or AC30 - with reverb, spring tank in the foot of the speaker compartment a là Fender? This must at some point have been a consideration. Something to come back to in another entry.

AC30 serial number 6019 before renovation. JMI reverb module and tank (with single spring) added in the 1980s?

Last, for the time being, simply to note that precious few early examples survive today of the models listed in the entry below - nor for that matter of the Watkins "Joker" with built-in tape echo, brought to market by Charlie W. in late May '62. More to come on the matter of survivals (or not) shortly.

15th October

A short-list of the principal British-made amplifiers with built-in reverb that were available in early 1962, i.e. in the months preceding the introduction of JMI's new AC30 Super Reverb Twin:

BIRD: "Golden Eagle", from January 1962: - 4 inputs, two channels, tremolo with footswitch, built-in reverberation, 25 watt output, 15" Goodmans speaker. 75 guineas. Nothing is said of Hammond.

HOHNER: "Ampleco Reverberation Echo", from January 1962: - 4 inputs, two channels, tremolo on one, reverberation on the other, 15 watts output, two 8" speakers. "Fitted with the genuine American Hammond echo unit - the echo you can really turn up!". 52 guineas.

SELMER: "Truvoice Twin Selectortone Reverb", from February 1962: - 4 inputs, two channels, tremolo on one, reverberation over both, two heavy-duty 12" speakers. 105 guineas. Likely to have been fitted with a Hammond (as the "Diplomat" was a few months later), though nothing is said explicitly.

FENTON-WEILL: "Auditorium 30" and "Black Star", from March 1962: - Hammond reverb, general descriptions in the advert in yesterday's entry. The Auditorium consisted of two amplifiers in one cabinet. 105 and 65 guineas respectively.

In mid May 1962, the plain AC30 Super Twin was 125 guineas, the new Super Reverb Twin I, 150 guineas.

14th October (2)

Below, a quick shot of the Fenton-Weill advert for its new range, Spring 1962 - "Hammond Reverberation" a big splash, as one might expect from Henry Weill's piece (previous entry).

Weill began advertising the range in the popular music press in late March. On the 14th April Jennings published its first mainstream advert for the standalone "Cliff Richard" stand-alone reverb unit.

Shots of some of the spring reverb assemblies designed by Jennings have now been collected together here, further material to be added shortly.

14th October

Some notes on amplifiers (in general) with built-in reverb in 1961 and 1962. The starting point is an article published in February 1962 by Henry Weill, manager of the Fenton-Weill company (based in Acton, West London), entitled "Today's Guitarists Can Play In 3-D". His key points were:

1: By the NAMM show of July 1961, use of the new Hammond spring assemblies (and driver transformers) had become the norm in those American-made amplifiers fitted with built-in reverb.

2: Europe was different. Hammond assemblies were difficult to obtain. Stand-alone tape echo units were the preferred thing. He does not explicitly mention drum or disk echo machines (e.g. the Meazzi Echomatic).

3: Spring reverb units were generally well suited for use in amplifiers (only one mild drawback). Anyone who wanted true (repeat) echo could use a stand-alone unit.

The reason for the article? Weill had a new range of amplifers incorporating Hammond spring reverb units to promote - the "Auditorium 30" and "Black Star" being the principal models in view.

Jennings, as is well known, took an entirely different path - more tomorrow.

13th October

Mike Smith of the Dave Clark Five trying out an early Vox Super Continental organ at Dartford Road, 1966, watched by Reg Clark. Picture from "The Vox Story", ed. Petersen and Denney, p. 38. It is possible - no more than that - that this was the organ shown at the Frankfurt Fair in March.

To judge solely from the photographs currently known, the group were no strangers to the Works. Later on Dave Clark was appointed a sort of roving ambassador for Vox by Tom.

12th October (2)

Thanks to Gene and to Chris, entries for three more late AC10 Super Twin Reverbs have been added on this page: serial numbers 3273, 3274, and 3292, all likely to have been exported to the USA early on.

12th October

The Jennings Christmas party, either 1952 or 1953 (the former more likely), music courtesy of a Minivox and Univox. The Minivox so far as one can judge was advertised only in early 1953 - see this page.

Derek Underdown's photo. Derek joined Jennings in June 1952, so this will probably have been his first Christmas there.

11th October (2)

Jennings Univox J6 serial number 2037: stickers on the keyboard assembly, which was produced for JMI by Herrburger Brooks in Long Eaton. The Univox action, as it turns out, is a Herrburger patent, applied for on behalf of the company by Leslie Astell on 18th June 1952.

The serial number on the body of the keyboard section, which has capacitors dated 1953 and later 1954, is 2037. "2346" is likely to be the number of the action assembly. "Style: NEW TYPE, SQUARE FRONT".

Patent Application No. 15322/52.

Cross section of the action.

Patent granted in September 1955.

Cross section (and other details) of the action.

11th October

Chris Squire, c. 1967, with what may be an AC30 Super Twin 2 set from the first half of 1962.

10th October

Two further AC30/4s - from late summer / autumn 1961 - recently come to light: serial numbers 4635B (preamp redone) and 4646B (original cabinet cut down to form a sort of Super Twin top, chassis only, no speakers), text entry for the latter here, pictures of both and an entry for 4635 to follow.

8th October

At the other end of the spectrum, vents on cabinet tops first appear on the new split-front cases adopted by JMI in late 1960 / early 1961, though with one principal exception - the AC2, which had a split-front but plain top through to later 1962 when the new larger cabinet came in, serial numbers in the 2400s - examples on this page.

An AC10 "Throwback" from late 1960 / early 1961. The AC10 was in all likelihood the first model to have had a split-front cabinet with top vents.

7th October

Around Spring 1964, the final genuine instances of brass vents, AC30 Super Twin serial number 13273 being close to the point of discontinuation (i.e. end of stock). Serial number 14331 has repros. The holes for the lugs of the original black vents are still there on the cabinet top.

The other thing to say is that almost all Super Twins with numbers in the new sequence beginning at 2500 had black vents from factory. Serial number 2541 looks to be one of the rare (original) exceptions. Serial number 2591, recently sold on ebay.uk, is not. Watch out for those repros.

AC30 serial number 13273. Possibly repros (just a wee bit bendy), but the originals were evidently brass too.

Serial number 14331.

6th October

A detail of the (plastic) vents of AC30 Twin serial number 14650, "VOX" picked out in white - original or added by some later owner? Remnants of paint also on serial number 14595 or just grime? Probably the latter in both cases.

AC30 serial number 14650.

AC30 serial number 14595.

5th October

November 1964 for "Musicland", more elaborate than usual, the illustration of the "Guitar Set" borrowed from the JMI "Precision in Sound" newspaper-format catalogue (of autumn '64).

November 1964.

4th October

A Univox J5 from 1952 or 1953 sold some years ago. The recommendation seemed to be that something different or better could be constructed from the constituent parts. The green-coloured transformer was manufactured by Elstone (Elstone Electronics Limited), the speaker a Goodmans.

Univox J5, serial number unknown.

2nd October

A superb late Univox J6 - split front; black grille cloth; silver Elac speaker (10N/86); compartment for cables in the lid; and chrome gigster stand with break-apart "basket" (slotted together at centre) on top, the only instance of this later type of stand that has so far come to light. Thanks to G. for the picture.

1st October (2)

As a sort of adjunct to the entry below, a detail from one of the photos submitted by Tom to the old Patent Office in London in June 1963, all captions and logos blanked off by the clerks as they had no bearing on the submission. Cabinet "dress" did, however.

June 1963.

1st October

Black cabinet vents: occurences in the second, third and fourth quarters of 1963 are generally pretty sporadic. On AC30s with serial numbers in the 7000s and 8000s the vents are metal. In the 9000s one finds metal and plastic too (though never together on the same cab). In the 10000s and 11000s plastic becomes the norm, frequency of use increasing as production moves on.

If the soft (melty) plastic ones mentioned by Reg Clark were used for AC30s initially, the first quarter of 1963 is likely to be in view, serial numbers in the 6000s. No sign so far. The relevant cabinets that now lack vents evidently had brass - no tell-tale holes for the lugs of black ones.

AC30 Twin serial number 10408, plastic, slightly warped, three vents without logos.

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