VOX AC100 - UPDATES AND NEW INFO
2025
16th May
Thanks to Danny, a couple of shots of Jennings AC40 serial number 1215, ready for sale in late 1971. The page on the AC40 can be found here.
8th May
Below, thanks to Martin, a detail from a photo taken at the Russell Hotel Trade Fair in August 1965 showing among other things the rear of one of the new Vox Line Source 40 public address speaker columns with built-in transistor amplifier.
It is not immediately obvious where the mains cable plugged in. The rectangular socket at the base of the column looks to be a standard XLR rather than a Cannon LNE-32.
Review of the Fair, published September 1965.
4th May
An entry has been created for AC100 serial number 714, a late "100 Watt Amplifier". Pictures to follow shortly.
11th April
Part of a longer piece on Tom Jennings, mainstream Liverpool press, September 1964, the Beatles having been in the USA for near on three weeks. The group had a backup/spare AC80/100 amplifier section and Mal Evans a plentiful supply of replacement valves. There were however only three speaker cabinets (and trolleys) - one bass, two SDLs - the ones used and seen on stage.
It would presumably have been perfectly possible to replace anything damaged at one concert in time for the next.
15th September 1964.
10th April
Searches through various repositories of newspapers in the United Kingdom have brought to light - so far - a grand total of no adverts (listings) for the AC100 from local shops in the "provinces", i.e. outside London.
Some of the material from shops in London can be found on this page - to be updated soon.
6th April
Copied over from the Vox AC30 website, one of the earliest adverts for Vox in America illustrating equipment recently arrived (i.e. not simply reprinted from a photo supplied by JMI) - 1st November, 1964.
Left to right: an LS40 column; AC4; AC50 Foundation Bass; and an AC10 Twin. The guitars are: Vox Clubman; Dominator; Symphonic Bass; and Super Ace. The Clubman's hang-tag can be seen at left.
More to come on Vox in the USA shortly.
Cleveland, November 1964.
2nd April
Pics of serial number 2025 - a bass set from 1967 - have now been added on this page.
19th March
Thanks to Alan, pictures of an early AC80/100, mid or later 1964, its back panel replaced at some point with one from a later amp - serial number 1799. More to come shortly.
8th March
The firm that assembled the new solid state PA100 for Jennings (Jennings Electronic Industries) in 1973 evidently produced versions of the same amp for at least two other companies, the two currently known being Colorsound and FAL.
The version made for FAL normally had two sets of inputs for each of the first three channels, but no push buttons. As for the company that made the amps for Jennings, Colorsound, and FAL, the two chief runners would seem on the face of things to be Triumph Electronics (Purley) and A.P.T. Electronics (Byfleet). On balance, the latter feels more likely - in the mid 1970s Triumph concentrated mainly on valve amps.
Chassis with reverb tray mounted on top.
Colorsound PA100, reverb tray mounted with springs down.
A slightly different version of the board produced for the Jennings amplifier.
7th March
A Vox trade show wallet perhaps from the Russell Hotel Fair of August 1963. The "Guitar Accessories" brochure is part of a series of five covering various aspects of the Jennings range. The xerox is a copy of the catalogue of late 1963.
3rd March
The page on the Jennings J40 combo is in the process of being updated, new material from Dave M. and Steve W. - thanks to them - to be incorporated. A note will be posted when the updates have been fully worked in.
22nd February
A little on the sound testing of the AC100 SDLs produced for the Beatles, thanks to Geoff, who was present. The testing took place in the main assembly area of 115 Dartford Road, early August 1964. A number of the skylights in the sloping roof were opened, presumably to help disperse the pressure. Also present were Alan Pyne (who looked after repairs and the Artists' Loans Shed); Dick Denney; Derek Underdown; and various others. The volume was so immense in the confined space - certainly confined in relation to the stadiums in which the amps would be used a few weeks later - that Geoff had to stand at the far end of the area.
Reg Clark, JMI's General Sales Manager, also remembered the SDLs being tested outside the Dartford Road Works - reported by Jim Elyea, page 588 of his book. Perhaps the same day slightly later on (?).
The new SDLs were delivered to John and George on 9th August at Scarborough. The equipment went up from Dartford in the JMI van, probably driven by Ernie Sleight, Eddie Haynes (sales rep. for the south-east of England) a passenger. Dick Denney drove up in his mini, accompanied by his wife Dolly, and Alan Harding, his assistant. More can be found on this page. The picture below of John trying out the amp before the concert was taken by Eddie Haynes.
9th August, 1964.
3rd February
A plan of the first floor of the Russell Hotel, British Musical Instrument Industries Fair, August 1967, from a BMII brochure picked up there by Don Miller. Thanks to Martin for the photo.
Jennings had five rooms on the floor: 134A, 135 for organs (probably along with 134A), and 141-143.
Below, Don's name in the list of Thomas dealers who went on the trip to Europe, published in Billboard magazine, October 1967. His main shop was indeed in Graham, North Carolina, where Thomas sent the bulk of its material for his displays, not Elon (corrected in yesterday's entry).
2nd February
In August 1967, as a sort of fillip for its dealers, Thomas Organ arranged a European jamboree, timed to take in the BMII Trade Fair in London. One of the members of the tour was Don Miller, owner of Frank's Jewelry and Music in Graham, North Carolina. At the Fair, Don collected three wallets (among other things), kept over the years along with his Thomas Organ promotional material. One of the three - all are complete - is pictured below. A short piece on Don can be found here.
To date, stray items only from '67 Trade Fair wallets have turned up in the UK, and seemingly until now, in the USA too.
The Thomas Organ dealers, photographed before boarding their plane, Don somewhere in the crowd.
Detail from a photo of the JMI stand at the London Trade Fair, a small stack of wallets on the PA amplifier.
The wallet with Marauder brochure at front.
1st February
Below, the contents of the Trade Fair wallet illustrated in yesterday's entry: brochure for the Marauder Special guitar; flyers for the new ranges of organs and Gyrotone rotary speaker cabinets; the new JMI catalogues for amplifiers and guitars; wah-wah pedal demonstration flexi disk (removed from its backing card); select pages from the 1966 catalogue; "Vox Parade" double-sided "newsletter".
Tomorrow, the story of the wallet - how it came to be in the USA (until recently).
31st January
Thanks to Jim and Martin, a shot of one of the JMI promotional wallets handed out at the BMII Trade Fair in August 1967. More to come shortly. A page on JMI's presence at the Fair can be found here.
24th January
A couple of pictures to illustrate how serial number plates were attached on Vox "Metal Clad" public address amplifiers - with araldite. Many doubtless came off early on, the result of being heaved in and out of vans.
Underside of a MC50 amplifier from 1965.
Underside of a MC100 amplifier from late 1964, plate gone, only the swirls of araldite remaining.
23rd January
Just to note that pictures of AC100 serial number 736 (00736) have recently been posted on FB. The entry for the amp - on this page - has been updated.
20th January
Thanks to Angel, pictures of a Triumph / Jennings AC100 from later 1971, possibly 1972, in superb original condition. The amp is one of a number sold without logo and serial number plate. The main page on the Jennings AC100 can be found here, the amp below pictured in the section towards the end of the page.
19th January
Thanks to Marc, a couple of new pictures of AC100 serial number 496, late summer 1965.
8th January
Two further sightings of early JMI Line Source 60 public address speaker columns (4 x 12"), late 1965 / early 1966, a single with the shop plaque of "Musikhaus Hummel" in Frankfurt but currently in the USA, brown grille cloth, type of speakers unknown; and a set of two, currently in Europe, original stands present. All three have the distinctive band (dropped later on) across their fronts. More on Line Source 60s can be found on this page.
Thanks to Kevin for signalling the existence of this column. If the brown grille cloth is original, which it may (just) be, then a very late instance.
Thanks to Joop.
2024
29th December
Vox Line Source 40 (LS40) public address column speakers in America, late 1964 to late 1965. The earliest dated picture that has come to light so far is from March 1965 (below). The LS40s in view are English-made, flown over to the US for the Thomas Organ Company to distribute and sell:
March 1965, pictured with Hal's Vox AC4 and Stroller guitar.
The columns will have had "Jennings Musical Industries" identification plates on their backs, no mention of Thomas Organ. An overview of JMI's production can be found on this page.
For its catalogues, Thomas, as was its wont, gave the columns a fancy "Swinging London" name - the "Grenadier" - and designated the model for its inventories as the "V-1-20". Below, a detail from the pricelist of April 1965:
In the pricelist of September the V-1-20 is $295.
Although English-made equipment remained the norm through to the autumn of 1965, Thomas had in the meantime made good progress with plans for its own production lines of Vox equipment, primarily to cut the costs of shipping (though that evidently was not the only reason). Dick Denney duly went to Sepulveda to advise. The story of Dick's time there in late October / early November 1965, and an outline of the various matters discussed, can be found in Appendix 3 of the "Vox Story", ed. Denney and Petersen (1993), which gives a transcript of the Thomas report of the visit - fascinating reading and key to understanding how Thomas got its own production going.
On page 144 the matter of speakers for Line Source columns comes up. The text is worth quoting:
"Various speaker samples were compared to those used by Jennings in this application [the LS40]. No American speakers were found amongst the available samples which gave identical tone and performance to the English version. Here it was not so much a case of speakers being better of worse, but it is our desire not to alter the present sound characteristic of the English unit. Speakers have been purchased from the English source for the first releases of domestic production and we will continue to sample speakers from domestic speaker manufacturers until a satisfactory equivalent is obtained."
The English speaker manufacturer was of course Elac, and these were fitted to the first American-made columns - the "V-9". Below, some examples. The columns have Thomas identification plates at back, standard Thomas textured vinyl (not basketweave), paper stickers inside bearing the serial number of each column, and Elacs, as mentioned. Thanks to Ihor for the first three pictures.
No serial number was stamped on this plate.
Column number 992082.
The V-9 is on the right: main case made of plywood, the baffle and back panel chipboard (particle board), replicating the construction of the English-made cabinets of 1965.
Details of another set of V-9s, pictures thanks to Glenn - the serial number 992323 machine-stamped on the metal plate:
Rear, showing the closed back.
The serial number plate.
The highest column number (on the paper stickers) known at present is 992999. If the sequence began at 990000, then Thomas is likely to have made and sold around 500 pairs from late 1965 to around mid 1966. If on the other hand the starting point was 992000, which is perfectly possible, then of course around 400 made. During the course of 1966 changes that are not really germane here were brought in, and the model redesignated as the "V-1091", which is perhaps the most familiar version of the model.
20th December
A note on white warning plaques. The earliest AC50s with known serial numbers - 1004 and 1005 - were fitted with a type of plaque (Type 1) visibly different from the type of plaque that came shortly afterwards and remained standard into 1965 (Type 2). The earliest Type 2 plaque known at present occurs on AC50 serial number 1028 [*not number 1034 as previously stated].
The AC50s issued to The Beatles and The Dave Clark Five evidently had no warning plaques of any sort.
Type 1 plaque, AC50 serial number 1004. The same type is also found on AC50 serial number 1005.
Type 2 plaque. AC50 serial number 1034.
The same quick transition from Type 1 to Type 2 can be seen on AC80/100s. Bill Wyman's first amp - serial number 150 - had a Type 1 plaque, the change to Type 2 taking place by serial number 162.
Type 1 plaque, Bill Wyman's first AC80/100. Although the print resolution is low, note the amount of white space above "WARNING".
Type 2 plaque, AC80/100 serial number 162.
Type 2 plaque, AC80/100 serial number 178.
25th November
Thanks to Phil, pictures of Jennings AC40 serial number 1197, speakers dated November 1971, can now be seen here. Pics of Jennings JV serial number 1188 to come.
AC40 serial number 1197 (at right) with JV40 serial number 1188.
22nd November
Copied over from the Vox AC30 website. Published in "Music Maker" magazine, April 1967, "The Beakles", miniature drum kit, AC30s, AC100, and guitars made by Mick Bennett of JMI. Mick was responsible for prototyping many of JMI's guitars, cabinets, and cases through to 1968.
19th October
Thanks to Daniel, pictures of AC100 serial number 2108, mid 1967, have been added here.
AC100 serial number 2108.
18th October
Just to add in relation to yesterday's entry, "Emihus" zeners first come in towards the end of 1965. Serial numbers 796, 902 and 917 still have gold-coloured zeners made by "International Rectifier".
17th October
Some notes on the bias circuit of the AC100 mark 2, later 1965 through to 1968.
Detail from the circuit diagram for the AC100 mark 2.
As in the "100W Amplifier" of late summer 1965, the bias voltage was clamped by a pair of zener diodes - see this page. For the AC100 mark 2, JMI turned to "Emihus", a subsiduary of EMI based in Glenrothes. The "Hus" part of the name was the original owner - Hughes International (UK), part of the Hughes Aircraft Corporation.
The 20v diode across the width of the board was a "HS2200", the 15v diode across the two solder terminals a "HS2150".
Detail of AC100 serial number 1579.
Below, a detail from the "Emihus" specification sheet, the columns left to right being: part number; zener voltage; tolerance (in %); max. zener current (unspecified); dynamic resistance (in ohms); max. dissipation (in mW); type of connection (A1 = axial, flying leads).
Detail from the Emihus spec. sheet.