Vox AC80/100 (early AC100) serial number 173


May to July 2021

30th July

Further pieces relating to the - a short article on Tom and the company, and a summary of business transacted at the Fair. The "Frankfurt secret" (mentioned in the former) is likely to have been the AC100 SDL. In photos of Frankfurt '65 - see the page linked above - the amp is captioned "The New Beatles Model". An advert for it followed swiftly in the trade and professional music press (to be posted tomorrow).

Vox at the Frankfurt Trade Fair, February 1965

Vox at the Frankfurt Trade Fair, February 1965

29th July

One of the ads placed by Jennings to accompany preview reports of the Russell Hotel Trade Fair, August 1965, along with the printed report of the Jennings stand.

Vox at the Russell Hotel Trade Fair, August 1965

In the inset picture, The Kinks at the NME Poll Winners' Concert, April 65, published in a section of the journal devoted to the Fair printed on yellow paper. The photo was one of a batch later passed to Thomas Organ for marketing purposes.

Vox at the Russell Hotel Trade Fair, August 1965

The Guitar-Organ, two-manual Continental, the M.3 (Mark III) Mixer unit, MC150 public address amplifier, Escort guitar, and more. The pricelist was published in November.

26th July

Thanks to Robert Valentine, the page on the has been updated and corrected - the event: - the "International Audio Festival" in April, not the AMII Trade Fair as previously stated. Also to say, that Robert saw that he is pictured in "The Best in Sound" advert posted a fortnight ago, detail below.

Vox Works, Dartford Road, 1961

Music trade journal, May 1961. Ken is in the foreground, then Brian, Robert at the far end.

22th July (2)

A further reference (from April 1955) now added to the page on the . The most recent acquisition among the "adjacent smaller premises" mentioned is likely to have been number 117, the old Fish and Chip shop. The painted advert on the side of the building can still be seen in photos from 1965.

Jennings Musical Instruments, 115 Dartford Road

Music trade magazine, April 1955.

22th July

Some JMI promotional material for the - a great double-page advert, and the preview blurb for the show.

Vox at the Frankfurt Trade Fair, 1965
Vox at the Frankfurt Trade Fair, 1965
Vox at the Frankfurt Trade Fair, 1965

Mufag continued to serve as a JMI distributor in West Germany through to 1968.

16th July

A JMI advert principally for Public Address equipment (a relatively uncommon thing), December 1964. Along with the "Precision in Sound" broadsheet catalogue, this gives a view of the state of affairs following the Trade Show of 1964 - but there is no mention of the 100W "all-in-one" PA amplifier (with built-in echo and reverb) that was showcased at the Russell Hotel. Plans for commercial production are likely to have been quietly shelved.

Vox PA advert, December 1964

Music trade press, December 1964.

12th July

M usic trade journal, August 1964, a double-page fold-out printed on yellow paper, to accompany the previews of the . A double-page advert for the new range of Thomas organs distributed by JMI figures in the journal a few pages later.

Vox at the Russell Hotel Trade Fair, August 1964

Music trade press, August 1964.

11th July

The page on the JMI stand at the has now been started, thanks to Robert Valentine for the pictures. [The event was the "International Audio Festival" in April, not the AMII Fair as previously stated]. More on JMI/Vox at Trade Fairs in the UK, Germany, and the USA coming shortly.

Also coming shortly, more on the development of the - work carried out, and plans that did not come to fruition. Below, an advert placed in the music trade press, May 1961, showing the interior of the factory. A copy of the pre-press flyer is already on the page linked above, but the magazine gives the terminus ante quem for the undated photos inset.

Vox Works, Dartford Road, 1961

Music trade journal, May 1961.

8th July (2)

A short report of Royston's acquisition of Jennings in the music trade press, February 1963. Tom had signalled the plan for a new factory building in mid 1962. How did JMI come to Royston? Very probably through Burndept Electronics, a major contractor for JMI in '62 (and beyond) and a member of the Royston Group from c. 1960.

Royston's acquisition of JMI, 1963

Music trade press, February 1963. "The Guardian" had already noted the acquisition in January.

8th July

This is the advert put out by Jennings to accompany the review of the Russell Hotel Trade Fair of August 1964. JMI's standard practice from this point was to place a full-page advert in the trade press shortly before the AMII Fair, at least one double-page spread in the trade journal supplements on the Fair (effectively advance reports), followed by one in September to accompany the reviews.

The catalogue described in the ad as being "in the form of a newspaper folder" became the "Precision in Sound" broadsheet catalogue (described in this way in a trade journal in late 1964).

Jennings stand, Russell Hotel Trade Fair, August 1964

7th July

The journey from Dartford to the Frankfurt Fair, described in March and April 1964. Tom probably flew with the other members of the British contingent. Material on the Fair is being assembled .

Jennings at the Frankfurt Trade Fair, 1964

Jennings at the Frankfurt Trade Fair, 1964

6th July (2)

Just to note that in 1964, the NAMM show moved from its traditional venue, the Palmer House Hotel in Chicago, to the Conrad Hilton. Jennings attended the last show at the Palmer House (in 1963) - .

Jennings at the NAMM Trade Fair, Chicago, 1963

6th July

A brief note in the music trade press on Jennings in Chicago, June 1964. If the text is to be followed, the Thomas Organ Company evidently had not yet confirmed its interest in being sole distributor - that was announced two months later in the "Million Dollar Deal" made at the Russell Hotel Trade Fair in August.

The distributor in Milwaukee may have been Zeb Billings.

Jennings at the NAMM Trade Fair, Chicago, 1964

5th July

New material on the Russell Hotel Fair, August 1964, coming shortly. Below, a better version of the ad for the Fair of August 1963, published in a special section, "Music Trades Review", printed on pink paper. The page is in the orientation intended by its designer. The version posted yesterday has been turned clockwise so as to make its printed text and illustrations vertical.

JMI advert for the Trade Fair, August 1963


4th July (2)

A version of a well-known ad (published in "Beat Instrumental" magazine etc.) printed specially for the . Above "Jennings Musical Industries Ltd" is the line: "See the complete range of VOX equipment with many new surprises at the British Music Trades Fair."

The only item illustrated that could really be described as "new" is the Foundation Bass speaker cabinet. Jennings generally avoided giving away too many secrets / surprises in advance of these Fairs.

JMI advert, music trade press, August 1963


4th July

This is the most extensive review of the Jennings display at the , that has so far come to light. The speaker configurations for the T60 are described; the electronic guitar tuner - the "Transtuner" - is named; and a more extensive account of the Wireless Microphone system given.

JMI at the Russell Hotel Trade Fair, August 1962

JMI at the Russell Hotel Trade Fair, August 1962

2nd July

Jennings stand, Russell Hotel Trade Fair, August 1963. Left to right: A.F.Cameron (Export Manager); Paul Jennings, Tom's son and manager of Musicland, Bexleyheath; J. Willament (Sales Manager). Willament was succeeded by Reg Clark a couple of months after this picture was taken. On the back wall, Phantoms in three colours. In the foreground, probably the Star drums mentioned in the press - .

Jennings stand, Russell Hotel Trade Fair, August 1963

1st July (3)

A piece published in "Record Retailer" in late July 1963 suggests that JMI had been the sole British representative at the NAMM show in Chicago, just ended - .

This it turns out was not strictly true as the piece below (published in another paper in August) indicates. Challen Eavestaff and Alfred Knight also attended. However, it should be said that in the early 1960s manufacturers of pianos and manufacturers of electronic instruments had formed themselves into different camps - a sort of natural separation. The piano section of the Frankfurt Trade Fair, for instance, was quite distinct from the section comprising Jennings, Rose Morris, Selmer, and so on. All perfectly understandable. Presumably the report that cast Jennings as the sole British representative at Chicago, simply failed to say "sole British manufacturer of electronic instruments".

British music trade journal, August 1963. Picture taken from a very tightly-bound volume, but the text should be legible enough.

1st July (2)

Below, a detail from a great Vox ad placed in a British music trade journal, January 1963 - more on the whole later. Clockwise from top left: a Vox-branded Reslo ribbon mic; a Jennings-branded Meazzi drum echo unit; a Line Source speaker cabinet in beige vinyl; a white Phantom bass guitar; and AC30 Twin; and a Jennings D2 organ.

Of greatest interest is the Line Source speaker cabinet. The page on the LS40 will need revising. Evidently these were brought into being in late 1962 and issued without stands until late 1963.

Early Line Source speakers were doubtless exhibited at the Frankfurt Trade Fair, late February 1963 - .

Detail of a JMI ad for Vox equipment, January 1963

1st July

A great pic from a tightly-bound British music trade journal of the Jennings stand at the Russell Hotel Trade Fair, August 1962 - the new Vox Transonic at left, and at right, one of the new T60s, still at the prototype stage and remaining so until early November (statement from Jennings). The page on the has been updated, and will be expanded further shortly.

Vox at the Russell Hotel Trade Fair, London, August 1962

27th June

A short "preview" of the JMI showing at the Russell Hotel Trade Fair, 1964. Two things are of particular note in relation to amplifiers - "a new look for all 'Vox' Amplifiers" and a "surprise version of the ultimate in 'Vox" Amplification".

The "new look" is likely to be black grille cloth. This did not come in straight away however. AC30s for instance were still being sent out in brown in late '64 / early 1965.

The "ultimate in 'Vox' Amplification" is probably the two AC80/100 SDLs described in reviews as having been on show. AC80/100s will not have been widely seen at this point. The Beatles had been issued with theirs in early August. But prior to 24th August (the first day of the Fair), John and George had only used their amps and cabs at Scarborough on the 9th, and on the first five dates of the North American tour. Whether wire photos of the group on stage were published in the British press, 19th-23rd August, remains to be ascertained (one way or the other).

The only other thing that the "ultimate in 'Vox' Amplification" could be - possible but not particularly likely - is the new "All in One" PA Amplifier (with Echo and Reverb), widely reported in retrospective accounts of the show.

Vox at the Russell Hotel Trade Fair, London, August 1964

"Music Trades Review", August 1964.

26th June

This preview report of the Jennings showing at the is the earliest mention so far of the company's "General Public Address Equipment". It is likely that the Fair was the first public unveiling of the PA amplifiers and certain of the PA speakers. Jennings had long provided sets of floor standing and wall mounted speakers for its organs - and in certain instances (in the late 1950s) these are recorded as having been used for public address purposes. But Frankfurt is the first mention of the new category "Public Address".

Vox at the Frankfurt Trade Fair, March 1963

"Music Trades Review", January 1963.

25th June (2)

Note that the date in the entry below has been corrected.

25th June

Some new material on the Russell Hotel Trade Fairs coming shortly. This will push some of the other things back a little. The existing pages on the Fairs will need expanding and perhaps dividing up.

Below, a shot taken in the Jennings stand in the Wharncliffe suite at the (NOT 1964 as previously stated). The tall man at right is Joe Benaron.

The traditionalist music trade magazines (as the one above was) seem generally to have found the Thomas organs the most interesting thing about Jennings at this point.

23rd June

The new page on the has now been started. Further material will be added next week.

The front page of a dedicated review section in "Record Retailer", 22nd August, 1963.

19th June (2)

A short note, 23rd July, 1964 on the new AC80/100s for John and George. The Hollywood Bowl concert had been arranged for (and took place on) the 23rd August '64.

"Dartford and Swanley Chronicle and Kentish Times", 31st July, 1964.

The new amplifiers were first used on stage in Sweden at the end of July - see the material collected .

19th June

This entry has been ported over from the Vox AC30 website updates page. Strong links were first forged between the Thomas Organ Company and Jennings in the late summer of 1963 when Jennings took on the distribution of Thomas organs in the UK. The arrangement was announced at the Russell Hotel Trade Fair in August, and separately in the music industry press in September.

Initial discussion between Tom Jennings and Joe Benaron, president of Thomas, is likely to have taken place at the NAMM Show in Chicago in July (see below, entry for 13th June). Jennings was the sole representative there of the British musical equipment manufacturing industry.

Two things flowed from the arrangement: - Jennings further scaled down its own production of console organs; and in the late summer of 1964, Thomas agreed to distribute Jennings equipment (Vox) in the USA - the "Million Dollar Deal". To anyone who knew that Jennings distributed Thomas equipment, this cannot have been too much of a surprise.

Jennings went great guns on Thomas, offering 13 of the company's organs by November 1964, along with various accessories and teaching aids. The organs offered in the earlier part of 1964 (which is still building).

18th June

In August 1963, "Record Retailer" magazine published a plan of the various stands at the Russell Hotel Trade Fair. Jennings had two spaces - one on the ground floor in the Winter Garden (a covered courtyard) at the hotel's centre; and a second larger set of rooms in the Wharncliffe suite on the first floor.

Jennings had rooms "N" and "A", left front in the Winter Garden; and rooms 141-143 on the first floor. "Record Retailer's" own stand was not far from Jennings' in the Winter Garden.

Below, an old ground plan of the ground floor of the Russell Hotel. In the Winter Garden were two rows of stands. A further two rows were set up beyond it in the Banqueting Room. Some of the other ground floor rooms were used too. Weill, for instance, had the Oak Room, called the Billiard Room at the time when the plan below was drawn up.

Image from the RIBA photo library.

Pathe newsreel footage of the Fair can be seen in the youtube video below. Tom Jennings and Dick Denney (holding a Phantom guitar) make a brief but unscheduled appearance.

17th June (2)

A report - 3rd November 1964 - of the readiness of the West Street Works in Erith: "completion" refers simply to the refitting of the building. Production of amplifiers began shortly thereafter: AC50s first, then in early Spring 1965, AC100s.

17th June

Updates to the section on are in progress. Pages recently added: Russell Hotel Fair, August 1962; a note on the Frankfurt Fair of March 1963, which was the first time Jennings had attended that event; and a note on Jennings's presence at the National Association of Music Merchants (NAMM) Show, Chicago, 1963.

Coming shortly, material on the Russell Hotel Fair, 1963, and additions to the page on Frankfurt 1966.

16th June

A shot of 119 Dartford Road taken in the early 1950s, now added to the page on the :

15th June

A plan of the displays at the (24th-28th August) printed in "Record Retailer", 20th August, 1964. The paper also published - on 13th August - a "preview" of the items the various companies would be exhibiting. Jennings was absent from this, however, as Tom liked to preserve an element of surprise at Fairs.

As can be seen, Jennings had two adjacent spaces in the hotel's Winter Garden, to its right, Beare and Company, which dealt mostly in classical instruments.

Material relating to the 1963 Trade Fair published by "Record Retailer" will be posted shortly.

"Record Retailer and Music Industry News", 20th August, 1964.

"Record Mirror", 29th August, 1964, from its report on the show. A better image to be supplied.

14th June

A note in "Record Retailer", 30th April, communicated by Reg Clark, relating to Jennings's plans for expansion - a new factory at Dartford Road, another two in Erith, and a London showroom. As it turned out, only two of the four buildings came about: - 117 Dartford Road was redeveloped; and in late 1964, JMI moved certain operations to a single factory in Erith: the , owned by Burndept, a fellow member of the Royston Group.

The delivery of equipment to the Royal Family was widely reported but produced little comment - different days. It is interesting that the publicised plans for expansion preceded the announcement of the "Million Dollar Deal", struck with Thomas, by four months - an extremely prescient move. The deal with Thomas was announced during the AMII Trade Fair, late August, 1964. JMI had already agreed in 1963, it should be said, to market and promote Thomas organs in the UK.

"Record Retailer and Music Industry News", 30th April, 1964

12th June

The note below, "Record Retailer and Music Industry News", 24th October, 1963, is the earliest dateable public mention by Jennings of the AC100 (AC80/100) to have come to light so far. In common parlance "doing a ton" meant reaching 100mph on a motorbike (normally) or in a car. "Ton up boys" were groups of bikers who had done 100mph or more.

The circuit diagram for the AC80/100 is dated 26th September '63.

7th June

A note on Derek Underdown's grid stopper resistors. In the AC50 and AC80/100 the value used is relatively high - 47K - their purpose being to prevent any low frequency oscillation in the EL34s. In certain Mullard data sheets for the EL34 (1956-57, but not 1962 and 1964) the total resistance recommended for the control grid (grid no. 1, EL34 pin 5) is 0.7M or 700K. The AC80/100, however, has 707K. The control grids of the EL34s "see" both 330k grid resistors in addition to the 47k stoppers - a small excess, but as nothing compared to the way in which the plates and screens were driven.

Detail of OS/036 with 47K grid stoppers and 330K grid resistors marked. The grid resistors in the AC50 are 220K, so the total is more easy going at 487K.

In terms of design, 47K stoppers seem to be a hallmark of Derek's amplifiers. One not only finds them in the G1/10 (un-numbered sheet of March 1958, and OS/004), but in a number of the circuits he designed for organs in the late 1950s. Below, a detail from the power pack and amplifier circuit for the Model H of summer 1958.

A detail of OOS/005 for the Model H organ. EL84s in this instance rather than EL34s. None of the amplifiers - more specifically power sections - designed by Denney employ high value grid stoppers.

5th June

A couple of items from a forthcoming set of ads and documents relating to Thomas's distribution of Vox in the USA in later 1965:

"Des Moines Tribune", July 1965. In his youth Red Scobee (Merle Nicholas "Red" Scobee, born 1907) had played bluegrass/hillbilly/country music with his Arkansas Ramblers.

"Fort Lauderdale News", 4th July 1965. Vox hits Miami in a big way, one of a series of adverts placed by the "House of Pianos and Organs".

29th May

A better picture of the Thomas Vox dealers assembled at JFK for their tour of Europe (to see among other things, the new JMI solid state range in London):

The banner reads: "Welcome / U.S. VOX DEALERS / August 1967 European Excursion / Organised by SIMMONS Group Journeys Inc. New York".

22nd May

An entry for AC100 has been made. Thanks to Tony for the pictures. The gap between the last cathode biased amps and the first "100W Amplifier" in terms of known serial numbers is 448 to 496. It seems unlikely that the change was abrupt. Quite what went wrong with the stamping of chassis numbers in the 400s is unclear. At least three stampings had to be corrected (on serial numbers 424, 430 and 448). The only change introduced in the chassis of the "100W Amplifiers" was the form of cut-outs for the main filter caps - perfectly circular, instead of the holes expanded with small excrescences in the late cathode biased amps.

19th May

Thanks to Rodney, copies of JMI circuit diagrams OS/058 for the Mark II mixer (October 1964), and OS/082 for the Mark III (June 1965), sometimes called the M.3 - in the JMI pricelist of 1967 for example. Below, details of the input sections and some notes preliminary to the updating of the page on mixers (link below).

The Mark II circuit corrected at least one significant flaw in the Mark I discovered by David, who assembled the Mark Is and some of the Mark IIs for JMI under loose contract in his front room at home. David's account . In common with the Mark I, the Mark II had three low gain inputs and three high gain. The transistors at input were germanium OC44s - also used at input in the Vox T60 amplifier. The gain and tone circuits - treble and bass, new in the Mark II - were driven by OC71s.

A detail of the front end of the "Mk II Mixer Unit" from OS/058.

The Mark III represented a departure from the "borrowed" Japanese circuit of the Mark I and II. There were five microphone inputs (high gain) and only one for music (low gain). Transistors at input were either OC71 or AC107, both germanium, the latter high quality, low noise. In place of these one also finds RCA 2N2613, as noted in the entry below, 16th April, where the American circuit diagram is given (V827). The latching front of the early boxes was done away with, and an all-metal housing adopted to match the housing of the new Metal Clad public address amplifiers. The Mark III's electronic design is likely to be the work of Derek Underdown and Alan Harding.

In terms of the US, the Mark II is pictured in the Thomas Organ "King of the Beat" catalogue of autumn 1965; the Mark III first appears in the "British Sound" catalogue of late 1965 (perhaps very early 1966).

Detail from the Thomas Organ "King of the Beat" Vox catalogue, autumn 1965. Still the first style wooden case with latching front, produced for JMI by P.A. Glock in Crayford, a mile or so up the road from the Dartford Works.

A detail of the front end of the "Mixer Mk III unit, 6 channel" from OS/082.

18th May

Some updates relating to the JMI Mixer units coming soon - in particular the Mark II (OS/058), late 1964 to summer 1965; and the Mark III (OS/082), summer 1965 to 1968.

4th May

Thanks to Tony, pics of AC100 serial number 448 (an entry will be made in the next few days). The amp is an AC80/100, cathode biased, and likely to have been assembled in the summer of 1965.

To date this is the only standard production AC100 to have come to light with a serial number in the range 430 () - 496 ().

The Welwyn cement screen and cathode resistors have the date code "WA" = January 1965. Note the cut-outs for the main filter resistors, with two smaller half holes top and bottom - found in the chassis of other grey panel cathode biased AC100s.