Vox reverb: introduction
1961 and 1962
In progress, October 2025
In some respects the outline presented backwards here is backwards, the English response to American developments first, then the start of things in America - principally the release by the Hammond Organ Company in September 1960 of a new compact reverb system, and the adoption - or rather implementation - of that system in early 1961 by makers of guitar amplifiers. The main focus of the page is Jennings throughout however.
1 - Henry Weill
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 was about to release and a new range of amplifers incorporating Hammond spring reverb units to promote - the "Auditorium 20", "Auditorium 30", and "Black Star" being the principal models in view.
Also to say that Weill had already sallied forth with a stand-alone reverb unit - the "Stereo Reverberator", brought to market in November 1961 (more on the unit further below). "Stereo" was a bit of a stretch, perhaps not quite as much as JMI's application of the term to its "Top Boost" circuit though - all for the most part just puff.
February 1962.
Jennings, as is well known, took an entirely different path in its approach to implementing reverb. A page on the various types of JMI reverb tank can be found here.
2: British-made amplifiers with built-in reverb (early 1962)
Below, 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 Vox AC30 Super Twin was 125 guineas, the new Super Reverb Twin I, 150 guineas.
3 - The Jennings "Cliff Richard" reverb, initially aimed at vocalists
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 earliest 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, and squarely aimed at vocalists.
The earliest dated advert for the "Echo-Reverberation" unit currently known, mid April 1962.
May 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 in the picture below - a Super Reverb Twin? 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 later.
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 amplifiers with built-in reverb produced by Fenton, Selmer, and Bird.
4 - The Vox Story (1993)
On page 61 of "The Vox Story", published in 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 main patent that Hammond took out for its tank is US3106610, granted in October 1963, applied for in January 1961. Naturally this only covered the design in view - not generically any and every tank-based system that contained springs and transducers for reverb.
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. An illustration of the tank, published by Hammond in September 1960, can be seen below.
As for the other patent noted on the sticker - 2,982,219 - that was a sort of first attempt designed solely for incorporation in organs. 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.
The patent for magnet and coil transducers - rejected by Jennings (and others) in favour of piezo/crystal pickups - belonged to Bell Labs (1932).
5 - America, 1960 and 1961
The new compact Hammond reverb assembly was first advertised in the American music trade press in September 1960, 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.
Detail from a Supro catalogue said to be from 1961 (if so, late). Just visible is the line at foot "Licensed under Hammond Organ Co. patents".
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. Weill's "Stereo Reverberator", largely based on Hammond's patent US2949805, 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.