VOX AC100 - UPDATES AND NEW INFO
2018 current (April-July)
A little more on serial number 150 and Bill Wyman's first AC80/100:
Serial no. 150 as published in 1999; and a detail of Bill's amp on stage, NME Poll Winner's Concert, 28th February, 1965. Although the angles of the shots are very different, one can nonetheless see that the diamonds line up perfectly. Note the diamond in the lower right corner. What appears to have shifted fractionally is the "BASS" logo.
Above, a composite of part of the grille cloth of serial number 150 and Bill's amp at the Mad Mod Ball, 4th April, 1964 - see below (29th July). The pattern of diamonds is very close, but there are visible differences lower right.
Above, serial number 150, bought second-hand from Cecil Gullickson's Music Mart., Orlando, in 1966. It is said to have been sent out to Florida from JMI refurbished.
The back panel, photographed in 1999.
The Mad Mod Ball, Empire Pool, Wembley, 4th April 1964. The back of Bill's first AC80/100 - two latching Cannon XLR-3-13 speaker sockets one above the other, and a Bulgin mains socket - is just visible through the railing at right. Is there an unused screw hole on the top edge of the back panel above the uppermost speaker socket?
The Mad Mod Ball - the stage, showing the early AC50 (and cover) as spare.
Above, a detail from a pic. taken in July (corr.) 1964, again showing the back panel of Bill's amp. The arrow indicates the reflective black of the Bulgin mains socket and connector.
Above, a schema of the back panel of 150 and Bill's amp. Whether 150 and Bill's amp are one and the same remains to be seen. Panels were fitted out at Dartford Road and tend to be similar for batches of amp - see for instance numbers 177 and 178.
The page on the changing arrangement of AC80/100 and AC100 back panels now updated.
A great shot of the Beatles, Las Vegas Convention Center, 20th August 1964.
Eight of the early AC100s (1964 to summer 1965) lined up for photographing. Shots of their back panels are on this page.
Above, three "100W Amplifiers" - fixed bias, no brimistor - with serial numbers in the 500s: 520, 531 and one unknown. All were exported to the USA in 1965, now back in the UK. 520 was in Minnesota, 531 in San Francisco, and the other in Kansas, though whether they were originally exported to those places is unknown.
Number 520 with its original cover (no logo), and two others.
Above, the back panel of number 520, no white warning plaque above the XLR socket, which seems to have been the case up to serial number 540 or so. At some point in the 600s, Amphenol XLR speaker connectors superceded the rectangular Cannon.
21st July (2)
A detail of the back of Pete Townsend's "100W Amplifier" (fixed bias, but not yet the AC100 mark 2), Richmond, 6th August, 1965. For surviving "100W Amplifiers", see this page.
Schema of the back panel.
The front of the amp.
A fair amount of the equipment given to The Who by JMI came back in pieces - three separate lots according to one source. Another report tells how Pete came in with an AC100, and said "These bleedin' things are rattling...". No surviving "100W Amplifier" will probably come to light therefore with a back panel matching the one caught in picture on that August evening.
Just to add, one can tell that it's a "100W Amplifier" rather than a cathode bias AC80/100 by the presence of the two screws on the top edge of the back board. Cathode biased amps only have one. White warning plaques were superceded by red when the AC100 mark 2 came into being.
A note on the zener diodes in the fixed bias circuits of the "100W Amplifier" (May/June and July 1965), and the "AC100 Mark 2" (July/August 1965 to 1967). These diodes are instrumental in keeping the voltage specified in the schematic (-35v) constant.
Above, the two zeners in serial number 531, a "100W Amplifier". The diodes were made by "International Rectifier", one 15v (part no. MZ15), the other 20v (part no. MZ20), both 3/4w max. dissipation. Gold-coloured "International Rectifier" zeners were used up to around serial number 1000. In terms of their arrangement on the board, the 20v normally extends across the width; the 15v bridges the two adjacent tags.
From around serial number 1000, a new type of zener was used: HS2150 (15v) and HS2200 (20v), both 1/4w max. dissipation. Above the original diodes still in place in serial no. 1579.
The amp below is the one above, published in "The Vox Story", David Petersen and Dick Denney (1993), p. 54. Compare the diamonds on the front. It is good to know this amp has a copper panel. It has now been registered here.
Picture originally printed here ("Guitarist" magazine, issue 425, October 2017), with the blurb: "A rare EL-34 powered Vox AC100 head with black, not brown cloth and copper control plate. Early examples had a thin edge to the cabinet."
The serial number of the amp is probably around the 220-230 mark. See this page.
15th July (2)
A great picture taken by Roger Kasparian of the Stones on stage, Paris, Olympia, 20th October, 1964. The JMI loan AC80/100 is visible at right. One can see how its back panel is arranged.
A slightly blown-up detail. The top corner of the white warning plaque aligns with back panel screw at left. The serial number plate is centre, and the mains and speaker sockets sit next to the outermost screws on the lower edge of the panel.
The distinctive thing is the position of the warning plaque in relation to the screw at left.
While no surviving amp matches precisely, it appears that arrangement becomes the norm around serial number 210, continuing into the black panel amps. Above, serial number 212. The second Cannon XLR is a later addition.
An amp recently sold in Japan now added to the strays page. The BASS runner from the cab has been applied to the amp front. New grille cloth all round.
Currently on Reverb, serial number 760, an AC100 Mark 2 with brimistor (one can tell from the presence of the red warning plate), made around August/September 1965. Some adjustments have been made to the circuit.
Another JMI black panel AC80/100 has come to light - serial number 268, currently in Finland. Number 269 is also in Finland, having been ordered (from Vaasa) from JMI in late '64. A small batch was clearly shipped out in 1965.
From 1967 to 1969 (and perhaps into the very early 70s), the main Vox dealer/agent in Finland was "PSO" - "Pohjoismainen Sähkö Oy":
Detail from a list of dealers in a Vox advert published in "Beat Instrumental" magazine, February 1969.
Whether "PSO" acted as principal in 1965 is at present unknown. Below, the handsome building in Helsinki:
A nice AC100 set currently on ebay, the amp with a serial number in the 800s.
8th July (3)
A detail from a shot of The Who on stage in mid 1965. On the chair, a flat-fronted metal clad MC100. For other versions of this amp, see this page.
8th July (2)
Click as ever for a larger image. McCartney's AC80/100 and Harrison's AC50 on stage, Cinema Cyrano, Versailles, 15th Jan. 1964. Note the control settings and the Bulgin fuseholders on the back panel of both amps.
McCartney's amp has large feet, lifting it clear of the top of the cabinet. Later AC80/100s had "furniture glides" - similar to small counters.
A new page started on the AC100s at the Richmond Jazz and Blues festival, August 1965 - the greatest number of AC100 SDLs ever present on one stage.
Just to round off the recent bass theme, two black panel T60s from 1963 - thanks to Mitch. The covers are from '64:
Further pics will be set up on the T60 website in the coming days. The amp on the right is no. 268; the one on the left has no serial number plate, but component date codes should give a terminus post quem.
A further early AC80/100 has come to light (thin-edged box, copper control panel, green Woden transformers):
The striking thing cosmetically is that there is a BASS flag but no VOX logo. Indeed, it seems as though one was never put on. None of the usual holes are visible at front or on the interior face of the baffle:
It is likely that this amp was used by JMI for promotional purposes. Below, Bill Wyman in a Vox advert with an AC80/100 also with no logo:
"Beat Monthly" magazine, December 1965. The full page is here (scroll to the foot).
Note that the alignment of the diamonds on the front of the amp pictured with Bill matches those on the recently surfaced amp. The serial number of the latter is 254 - well into the series of AC80/100s produced with black panels. Our amp, however, was certainly made at the same time as the other copper panelled AC80/100s - in 1964. What seems to have happened is that it did not leave JMI immediately, but was retained, and only given a serial number plate (perhaps for sale or simply for the records) later - in 1965.
Above, the Rolling Stones with an AC80/100 on stage at Fresno - BASS flag but no VOX logo. But the logo could of course have been knocked off.
Thanks to Steve W. and Tom W. for their help.
A further pic. of the three sizes of Vox bass amplifier (AC30 Bass aside) available early to mid 1964. The dimensions below are of the wooden case only (excluding height of feet and handle):
AC80/100, copper panel, thin-edged box: 19" x 7" x 11 1/2".
AC50, copper panel, thin-edged box: 19" x 6 1/4" x 10 1/2".
T60, black panel (at first), box covered with pebble pattern rexine: 15 7/8" x 4 3/4" x 10".
One of the things that's been striking in recent trawls through the small ads in the back pages of "Melody Maker" magazine, 1965-1968, is just how often Vox PA amplifiers and speaker columns come up. Something almost every week - the South of England well represented, the North not so much.
The ads fall into three classes: used items offered by individuals; used items in shops; and new sets also in shops.
So far as one can tell, the majority of amplifiers were made for Vox by Triumph Electronics in Purley, esp. after mid 1965, when Triumph was asked to produce fewer AC50s. Production of the AC50 was taken up in greater volume at the Burndept/Vox Works in Erith to compensate.
One of the quirks of the PA 50s is that they were given serial numbers in the standard guitar/bass AC50 sequence - so AC50 serial no. 02666 is actually a MC50, the designation "MC", given in catalogues and brochures, standing for "Metal Clad". See this page for other numbers.
Whether MC100s were given numbers in the standard AC100 run remains to be seen. None of the MC100s that have so far come to light survives with a serial number plate. See this page.
A great pic from Mick Wall's piece on The Yardbirds - for which, click here. Photographed on Friday 6th August, 1965, morning or afternoon - at any rate, before the stage was made ready for The Yardbirds' evening performance at the National Jazz and Blues Festival, Richmond. The trolley of the AC100 at left is an early one (Mark 1) with a basket top. JMI pressed eight AC100s into service for the concert - presumably for the most part loans.
17th June (2)
"Melody Maker" magazine, 3rd August 1968. A Supreme, a T60, an AC50, an AC30 PA amp with speakers, and an AC100 with two 2 x 15" cabinets.
"Melody Maker" magazine, 31st August 1968. An AC100 amp section for £60. After some weeks it was reduced to £55.
Just to signal the start of a new website on Vox T60 amplifiers. The site will build week by week - there's a good amount of material to follow.
"Naomi and the Boys", Singapore, 1966, with three AC100s, the amp section on the left in its cover:
Note that the speakers in the cab on the left are Goodmans 241s. For surviving examples of Vox SDL cabs with these drivers see this page, and serial number 1534 here. It seems that Vox used Goodmans in 1966 in cabs destined for export, the one in the pic above (and perhaps also its SDL companion) to Singapore, the two in the links to Italy, and another to the USA.
A cardboard dealer stand from 1964 and below it a photo of one in place in a music shop door, late 1964 or early 1965 :
Sold on ebay around 2015. 16" x 12" approx. The images are archived here.
A detail from a photo of Bradley's Music Shop, Leeds, published in "Beat Instrumental" magazine, January 1965. The poster at the bottom of the door advertises the film "What a Crazy World", starring Joe Brown et al.
Vox bass amplifiers, 1963-1964, out in the sun. Vox AC80/100 serial number 178 (autumn 1964) ; Vox AC50 serial number 1034 (early 1964); Vox T60 serial number 286 (mid 1963).
Just to mention in relation to the T60 below, all three pot codes are "JJ" - October 1962. The circuit does not have the additions dated 10th October 1963 on the second schematic (OS/O62).
Photograph flipped to show the pot date code.
Below, some quick pics of an early T60 amplifier (from mid to late 1963) - serial number 268. black control panel, box without vents. The Woden transformers have the date code "LT" = November 1962. The chassis, assembled by Burndept, has the stamped serial no. 01006.
A new website on T60 amps and cabs will be online next month.
The green cover probably from 1964 and one of a pair (the other being burgundy) is not original to this amp. All cables, visible in the second pic. are, however.
Vox advert in the programme for the Daily Express "Record Star Show", Empire Pool, Wembley, 21st March 1965. The full programme is available here.
Advert in the back of Melody Maker magazine, 21st September 1968 - Jennings at this point is "Jennings Electronic Developments", based, as the ad indicates, in the old JMI Dartford Road factory. It is interesting to see that the keyword is "VOX". Exactly what sort of Vox equipment was being sold is anyone's guess - most likely older valve things stored in the sheds at the back of the premises.
Later, around 1974/1975 when Tom Jennings stepped away from "Jennings Electronic Industries" as it then was, Alan Pyne, a former Vox engineer, purchased 117-119 Dartford Road along with the sheds at back, and set up in business selling numbers of the remaining Vox amps and creating new ones from those that had been left unfinished (among other things).
There are some great recollections of Pyne on this page.
During the time of JMI's collapse - late 1967 to spring 1968 - old amps left in the sheds can hardly have been of much concern. The new line, after all, was fully solid state. And the old amps were evidently of little interest either to the new incarnation of Vox - "Vox Sound Equipment Limited" (VSEL), which had come into being in early June 1968 - see Reg Clark's account in "Beat Instrumental magazine", available on the Vox Supreme website. It may be that Tom Jennings came to some arrangement, however, about the items. The small ad in Melody Maker suggests a new undertaking, a move to sell.
For material relating to JED and JEI in 1968 and 1969, see this page.
Melody Maker, 6th January 1968. Further ads for second-hand AC100s, for the most part from 1968, to come - these may have to go on a page of their own as there are a fair few. Production had come to an end, he beat boom was over, solid state was the latest Vox thing.
A new page has been started here, gathering together dealer ads and small ads for AC100s and PA amplifiers published in English and American papers and magazines in the 1960s and 1970s. The same has been done for AC50s on the AC50 website - click here. Both pages will be updated as new material comes to hand.
Melody Maker magazine, 17 July 1965. Sets of PA Amplifiers and Line Source columns offered by PAN.
Melody Maker magazine, 21st August 1965 - part of a report on the British Musical Instrument Industries (Associated Musical Instrument Industries = A.M.I.I.) Fair at the Russell Hotel. The 150 watt P.A. Ampliifer - also signalled in the "Beat Instrumental" report (Oct. 1965) - on this page.
25th May (2)
Melody Maker magazine, 29th May 1965.
The "Vox 100 watt P.A. Ampliier" was either a MC100/4 or MC100/6 - see the catalogue detail below. The MC100/6 was first shown at the British Musical Instrument Industries fair in August 1964 and put into production soon thereafter.
JMI pricelist October 1965.
The £65 for the unit offered by PAN at the head of this entry is not bad given the price new.
More to follow soon on the PA amplifiers - details will also be posted on these pages.
Melody Maker magazine, 3rd July 1965. The "St Louis Union", winners of a heat in the National Beat Contest, pictured with an AC100 and two large box AC50s. The AC100 at this date is likely to have been a cathode biased amp (an AC80/100 in other words).
24th May (2)
An advert for the Jennings shop placed in Melody Maker magazine, 20th and 27th March 1965. The shop as it was in late 1964 is pictured below.
From "Beat Instrumental" magazine, November 1964. One can just see an AC50 or AC100 with tall bass speaker cabinet (immediately right of the tree) in the window. Click as ever for a larger image. The premises were taken over by Macaris in early 1967.
Melody Maker magazine, 16th January 1965. The drawing of the AC100 had already been circulated in late 1964 and was republished full-page in "Beat Instrumental" magazine, March and April 1965 - see this page.
Melody Maker magazine, 2nd January 1965. Quite what the "Large VOX Amp" was is anyone's guess. Presumably the "100-watt VOX Amp" was either a P.A. amplifier or an AC100.
19th May (2)
A further snippet from "Beat Instrumental" magazine relating to the 1966 Frankfurt Fair - entry below.
"Beat Instrumental", February 1966. The "new range of Vox equipment" was the 7-series, which in actual fact was not ready for sale until June/July.
"Beat Instrumental", May 1966, signalling some further delay of the new series.
The 1966 Frankfurt Music Fair.
Above, the advert placed by Vox in "Beat Instrumental" magazine, February 1966. This was taken up (below) in variant form as an advert for Vox at the Frankfurt Music Fair, 27th February - 4th March.
Above, "Melody Maker" newspaper, February 1966, advertising the company's presence at the Frankfurt Musikmesse - Hall 12, Stand 2416/7. The Vox ad for the 1967 show is here. Note that the logo of the AC100 cab has an edge outline.
Serial number 880.
Below, an aerial view of the Frankfurt Fair showing Trade Hall 12 at the back of the complex.
Frankfurt Messe, photo taken in the 1970s
The complex as it is today. Trade Hall 12 is new. Many older buildings still exist though.
"Beat Instrumental" magazine did not print a review of the 1966 show. Normally only the British Musical Industries Fair in August was given serious coverage. However, we can be fairly sure that at least some of the items pictured in the adverts were exhibited, and perhaps a new 7120:
The location of the picture above is unattested, but in terms of date, Frankfurt is certainly a possibility. Early 7120s had already been issued to the Beatles. On the other hand, the shot could perhaps have been taken at the British Musical Industries Fair mounted in Russia, July '66. The intention to exhibit 7-series amps there is noted in "Beat Instrumenal" magazine, April '66.
Guitar Center advert in the Los Angeles Times, 1st February 1970. An AC100 reduced from $1000 to $299.
For the sale of a second-hand AC100 in Ottawa in 1966, see the entry lower down this page for 14th Feb.
One of Bill's adverts in the Chicago Tribune, 18th December 1973. In other weeks, the amp is priced at $150.
7th May (2)
The date code of the blue Hunts 16uf capacitor in the preamps of a number of AC100s with serial numbers in the 1900s - starting with no. 1905 - is "UYT" = 4th week of 1966. Notes have been added where relevant on this page.
Currently on Reverb, a Triumph-made AC100 Mk 2 (one can just see the brimistor in the second pic) in box no. 1274. Typical of Triumph are the short preamp tagboard, the orange rubber grommets in the chassis pass-through holes, the plain metal shrouded transformers, and the insulated stand-offs under the fuse-holder board. No stamped chassis number. The underchassis is signed "DE" = Dave Earp, who also signed off many Vox AC50s.
The amp was long reported (incorrectly) to be in a box with serial number plate 444 - see this page. Triumph-made AC100s are often assemblages of old and new elements. The mustard capacitors in this one for instance are from 1964. However, a date somewhere in the last part of 1966 / early 1967 seems probable for the amp's manufacture.
Above, a box of Arrow Switches. Although these of not of the type used by JMI in AC80/100s and AC100s, similar boxes must have arrived at the Burndept / Vox Works in Erith. The full name of the company was "Arrow Electric Switches". Its factory premises were initially on Hangar Lane, North London (1937-1961); then Brent Road, Southall, West London (1961-1968), and finally Plymouth (1968-).
Left, the metal, ball-ended, Arrow switch used on copper-panelled AC80/100s. Right, the famous Arrow "black bat" switch used from the second third of 1965.
22nd April (2)
Below (also posted on the Vox AC50 site), a couple of 18" Celestion speakers in Jennings blue from early Foundation Bass cabs (before mid 1964). One is a T1022, the other a T1079. Both are 8ohm. The speaker on the left may have been reconed.
For a short time prior to the introduction of the Celestion 18" driver in early 1964, Vox used the Goodmans Audiom 90, marketed by Goodmans from 1962/1963.
Vox recommended using two Foundation Bass cabinets with the AC100. When the high power Audiom 91 became available in the autumn of 1964 (blue label, 100 watts, 8 ohms, against the 50 watts of the black labelled 16 ohm Audiom 91), one cabinet would just about have sufficed.
Bill Wyman was an early user of two Foundation Bass cabs with his AC80/100s and AC100s.
A note from "Beat Instrumental" magazine, September 1967. Bill mentions 100 watt units, T60 cabs, and stadiums in the States. In actual fact he meant Foundation Bass cabs rather than T60s. Evidently he got through a fair few.
An early upright bass speaker cabinet, a T60 from late 1963 - the 12" speaker on a board over the upper 15" opening. The original speakers are still inside - one T530 alnico Celestion blue, one 15" blue Tannoy. Note the perspex logo. For cabinets equipped from the outset (in 1964) with two 15" drivers, see entries further down this page.
The Jennings pages will be moved to a site of their own shortly.
5th April (2)
"The Road" playing the cinema at Hailsham, Sussex. Picture originally posted here. Hard to tell for sure but the AC100 amplifier does look as though it's in a thin-edge box.
A new page added on a well-used JEI B3 bass speaker cabinet from 1974. Late JEI speaker cabs are fairly thin on the ground these days: