Picking up from the entry below, one can distinguish "Vox Sound Limited" AC50s made by "Dallas Musical Limited" from those made by "CBS-Arbiter" by the length of the serial numbers. Dallas amps have long numbers, all beginning "75" = 1975. Relatively few were produced. Some may have been assembled in the second half of '74:
Above the plate of a Dallas AC50 complete with original cover and warranty documentation.
AC50s sold by by CBS-Arbiter have four digit numbers beginning "5" = 1975, same style of plate as above (some differences in printing though), and "6" = 1976, new style plate:
10th April (2)
In February 1975, Dallas Musical Industries, which had picked up various elements of the Vox line following the demise of "Vox Sound Limited" in its first incarnation, itself went out of business.
"London Gazette", 6th March 1975. See also the entry further down this page, 25th October, 2018
Operations were saved, however, and AC50s continued to be produced into 1976. Below, a note from "International Musician and Recording World", May 1975 - from this page.
Note that Reg Clarke was the former Sales Manager of "Jennings Musical Industries" and "Vox Sound Equipment Limited". During the collapse of VSEL in early 1970 he joined Dallas.
A valve rectified AC50 mark 2, no serial number (probably originally in the high 1700s / 1800s), from the last third of 1964. The box has been regrilled and given new piping and a new handle.
Only a few changes from an electronic standpoint: the pots have been renewed, and the mains switch and voltage selector replaced (one can see the redundant voltages printed on it).
Visible Erie capacitor date codes are "IIT" and "HDT" = 33rd and 28th weeks of 1964 respectively. Mustard capacitor codes are "A/64" and "B/64" = first and second quarters of '64.
The chassis was signed off at Triumph Electronics (the assembling contractors) by Dave Earp. Thanks to Joe for the pictures.
Below, AC50 serial number 7247. The original CCL 16+16uf filter caps have the date code "L6" = December 1966. The amp will therefore have been made in early 1967. Thanks to Ian for pictures.
An introductory page on valve rectified AC50 mark 2s - JMI schematic OS/053 - has been set up here:
Serial number 1411, original link voltage selector still in place.
Just to itemise the "marks", as there is some confusion in the literature:
AC50 mark 1 - single channel, valve rectified, two inputs first, then four - OS/044.
AC50 mark 2 - twin channel, valve rectified - OS/053 "AC50/2 Amplifier" (the "2" either indicates two channels, or mark 2).
AC50 mark 3 - twin channel, solid state rectified - OS/072 "AC50/4 Amplifier Mk III" (the "4" now indicates four inputs).
The "marks" are major changes in circuit design. There is nothing to show that the single-channel four-input AC50 was ever known as the "mark 2".
The earliest AC50 mark 2s were produced under contract for Vox by Triumph Electronics in the last third of 1964. A good number were shipped to the States to supply Thomas Organ (to meet the terms of the "Million Dollar" deal). The sense comes across from the surviving amps that JMI stockpiled several weeks' worth of output from Triumph - perhaps more - to form sensibly large transatlantic shipments. Triumph was quite a small operation for most of its existence.
Around 500-600 AC50 mark 2s were made.
A new page has been begun on AC50s with serial numbers in the range 1300-1750 - a range encompassing three different formats of amp. All chassis were produced for Vox by Triumph Electronics.
Both panels of the serial number plate are always hand-stamped:
From around serial number 1750, the serial number was machine-stamped - part of the ever growing process of systemisation in the last third of 1964 - JMI scaling up to meet demand from America and the wider world.
Below, a trolley from late summer 1964 - the amp and cab pictured with it are from late 1965. Note the basket on top for the amp:
Detail of the trolley issued to Tony Hicks of The Hollies, picture from around August 1964.
23rd February (2)
A superb late AC50 Super Twin recently come to light in Scandinavia - "Vox Sound Equipment Limited", serial number 1045. A good number of amps were exported there (really "thither" I suppose) in the mid to later sixties. The principal dealers in Denmark, Norway and Sweden were listed by Vox in 1969:
VSEL list from February 1969. It may have been A.W. Cappelen that provided the equipment for the Copenhagen Jazz Festival, October 1969, many Vox solid state amps on stage.
Voltage selectors were prohibited in Scandinavian countries and generally removed when new amps arrived. Sometimes the Vox black and gold hang-tag was used to filled the gap, as in the case of the amp pictured above.
Three new lateish amps registered: 6375, 7014 and 7371. Further amps to come soon. Below, a page from the Vox solid state catalogue of early summer 1967. Both the AC30 and AC50 were still good sellers at this time.
Vox solid state catalogue of early summer 1967
The page on AC50s in small thick-edged boxes (inputs in diamond formation) has now been updated.
Abbey Road, Studio 2, July/August 1964. The AC50 belonging to Tony Hicks of The Hollies. Recording session for the album "In the Hollies Style", released in November '64. The number of diamonds on the grille cloth shows this is a large box AC50 speaker cabinet.
16th February (2)
Alexis Korner at the Frankfurt Jazz Festival, 24th March, 1968, with an AC50 Super Twin.
Two facts and some probables. Above, The Moody Blues with a thick-edged small-box AC50 Foundation Bass set, probably at the Marquee Club, probably September 1964. Picture from Getty Images.
The earliest photographed instance of a small-box thick-edged AC50 (with inputs in diamond formation) to have emerged so far comes from June 1964 - the "Migil Five" on "Thank Your Lucky Stars" - see this page and the entry below, 16th Decembber.
14th February (2)
A detail from a shot of "The Roulettes" on "Thank Your Lucky Stars", 13th June, 1964. Note the early AC50 - thin-edged box - at left.
A valve-rectified large-box AC50 from the last third of 1964, serial number 1508 on the plate. The style of the stamping is unusual though. It looks for all the world as if the serial number plate is a repro.
One normally finds smaller letters and numbers, as below:
Two channel, grey panel, valve-rectified, but in an original small box (thick edges).
Ray Ennis of the Swinging Blue Jeans with an early thin-edged AC50 Foundation Bass set to his left.
Four amps with serial numbers in the 3000s added on this page - 3124, 3468, 3637 and 3647.
Further pics of serial number 2790 can now be found here.
Serial number 2790, made by Triumph Electronics for Vox, solid state rectified, no brimistor. No date-codes visible. Probably made in mid 1965.
5th February (2)
Further pics of serial number 2612 can now be found here.
A nice valve rectified large box AC50 from late 1964 - serial number 2612 - made at the Vox Works / Burndept factory in Erith. Chassis no. 140. The Woden transformers have date codes "JV" = September 1964. Further pics to follow. Related Erith-made amps are on this page.
The two-input AC50 from Italy now with old grille cloth, replacing the new issue synthetic fabric it had been fitted out with a few years ago.
Below, details of the inner face of the baffle before the fitting of the new cloth and scrim:
A detail of one of the baffle screws. All eight are original and undamaged by rust or cross-threading.
The page on JMI flyers and catalogue entries for the Vox AC50 in 1964 has now been updated.
"Melody Maker" magazine, 29th February, 1964 - Vox advert promoting the Beatles' use of an AC100 and two AC50s on their first American tour.
For more on this ad, see this page on the Vox AC100 website.
24th January (2)
Jennings advert in "Melody Maker" magazine, 4th April, 1964: "Come and try the new Foundation Bass amp on demonstration":
Presumably this was the new two input AC50 in a thin edged box. The first advert for the amp appeared in February '64:
"Melody Maker" magazine, 1st February, 1964.
- see also the entry for 7th November, below.
AC50 serial number 1723, large box, produced for Vox in the last third of 1964 by Triumph Electronics. The amp is one of several batches fitted with a slot voltage selector. One occasionally finds these also on AC10s.
21st January (2)
The logo of the early AC50 - produced without stems and attached part by glue, part by small panel pins in the horizontal bar. The pins may be later additions. None are visible in the logo of serial no. 1005B
Logos of later amps had moulded plastic stems on the back that slotted into holes drilled in the baffle.
A detail of one of the cut-outs for the cage nuts in the amp below. The first batch, or couple of batches of chassis had these. Around 15 chassis were made per week. Thereafter, the standard square hole is found.
Detail of serial no. 1034B
A set of pictures of an early two-input thin-edged AC50 (copper panelled) to come. The amp was in Italy for a number of years. At some point before it went, the output transformer failed and was replaced with a unit made by R.F. Gilson of Wimbledon. Gilson (anonymously) made the Radiospares Deluxe transformers used in Marshall JTM45s.
The AC50's box was refurbished in Italy in charcoal tolex and given new production (synthetic) grille cloth. The latter will be replaced with old production brown and the piping (lacking at the moment) reinstated.
In common with other early two-input amps, the chassis has large cut-outs for the cage-nut fixings, and on the back panel a jack plug socket instead of an XLR.
Visible date codes: Hunt capacitors - "YSI" = 5th week of 1963. Potentiometers - "DK", "KK" and "LK" = April, November and December 1963.
The GZ34 rectifier was replaced in or after 1966 - it has the date code "B6E3" = Blackburn Factory, 3rd week of May, 1966.
The main page on two-input thin-edged AC50s is here.
Updates coming soon. Just to mention that a small trove of early Jennings Musical Industries material from 1961-1962 is being assembled on this index page on the AC100 website.
Better pics of the Lasky's catalogue from 1959-1960 illustrating a small selection of Goodmans speakers including the new Audiom 90 18" bass driver - £28 0s 0d. Info on the Audiom 90 is being collected together on this page.
The Migil 5 on the Morecambe and Wise Show, Saturday 27th June, 1964, 8.25pm, with a thick-edged small-box AC50.
Above, a detail from an issue of "Midland Beat", June 1967. The amplifier grille cloth is just under 4 diamonds tall - either an AC30 Super Twin or an AC50. AC30 Super Twin amps, however, are the same width as AC30 Super Twin speaker cabinets. The cab and trolley in the picture are considerably wider than the amp.
Note that the trolley has a single bar supporting the "basket" in which the amp sits.
It looks as though the Tubby Dunn combo had a fantastic early large-box AC50 set, much as one sees on set during the "Ready Steady Win" competition, August and September 1964:
A diamond-input amp just come to light - serial number 1207. Thanks to Sofus for the pictures.
Pot codes are "BL" = February 1964. For other diamond-input AC50s, see this page.
An AC50 from 1966 currently in the States with a variant runner at front. At least one other amp is known to have this type of runner. Thanks to Cy for the pic and info.
10th November (2)
Two new amps added on this page - 5237 and 5253.
Just a quick note on the part numbers stamped on various components. From late 1965/early 1966 these are for the most part JMI's own rather than those of the manufacturer. Thomas Organ, which distributed Vox amps in the States, had its own set of codes too - see the service manual at the foot of this page. The JMI numbers are five digits probably (though not yet verified definitively) beginning with the year - "66xxx" = 1966.
Part numbers of the AC50 pots are: 66181 (500K) and 66520 (1 meg).
Choke, part number: 66524.
Black-topped mains transformer, part number: 66522.
Black-topped output transformer, part number: 66523.
The black-topped transformers used in the Vox solid state range have part numbers beginning 13xxx, and identical sets of three letters stamped in white on the laminations or in black on the copper binder.
Marked on the mains transformer of an early Super Foundation Bass amp, the code - 13759 - and three letters stamped in white, "JSB" or "J58"?
The driver transformer is - 13478A.
Two versions of the Dave Clark Vox advert, the lower one from "Beat Instrumental" magazine, March 1964, the upper (with its rounded two-tone corners) from a yet unidentified source. In both the AC50 is actually a T60 amp. The Dave Clark Five had been issued with new AC50s and cabs in February 1964 for their residency at the Tottenham Royal.
Yardley's music shop, Birmingham. Photo published in "Midland Beat" newspaper, March 1965. A small-box AC50 with AC30 cab and trolley.
The "Daily Express", 1st February, 1975. The end of Dallas, which had taken on the production of a small selection of Vox items, and another end for Vox - the final curtain for the AC50
17th October (2)
For Vox displays at various trade fairs 1964-1966 see this page on the Vox AC100 website. Further material will be added there soon.
An early advert for the Midax horn from the Earl's Court Radio Show, 1956. Image originally posted here.
The picture below must be of the Frankfurt Musikmesse, March 1965. One can see a large version of the picture above on the back wall of the Vox stand to the left of Denney. The picture above shows the Stones, Ready Steady Go, 26th June 1964.
The picture below cannot therefore be the Frankfurt Fair, 1964. The Fair always took place in February/March annually.
The now well-known picture of Dick Denney at the Frankfurt Trade Fair, said to be March 1964. There is an AC100 with a Mark 1 trolley (a basket to hold the amp, rather than parallel bars); a T60; and in front of that what appears to be a large box AC50, also on a trolley with a basket top. Is this March 1964? A large-box AC50?
Below, a pic. of the Burns stand at the Frankfurt Trade Fair, March 1965 - from this excellent site.
A Lasky's catalogue of 1959/1960 advertising the Goodmans Audiom 90 and giving its price. The speaker does not figure, however, in the standard Goodmans catalogue of 1960.
29th September (2)
A detail from the Vox catalogue of 1964/1965, probably printed February 1964 - see the printer's runner "2.64". In 1963 the image of the Foundation Bass cab was used to advertise the amplifier section too, though the latter was not on sale at that time - still in development. See the advert below. The 1964 catalogue will be available soon in its entirety on the Vox AC100 website.
Page from "Beat Instrumental" magazine, issue 4, August 1963: "Separate amplifier cabinet provides a total output of 50 watts undistorted". The Beatles were issued with their AC50s - the first to emerge - in late December 1963.
Above, the Guarantee Card and envelope, hang tag, and price tag of AC50 no. 1101. The page on diamond input amps has now been updated to include those in thin-edged boxes.
The Goodmans speaker pricelist from January 1963 now added on the speakers index page.
The Guarantee Card of AC50 serial number 1101, presumably a diamond input amp (second third of 1964) given the format of the number "4/1101". A pity the date was not filled out. Better pics to follow soon.
Serial number 8270 - American-style logo, "AMPLIFIER" alone on the serial number plate - has been added here. Its chassis number is the highest to come to light so far. Thanks to Rich for the pictures.
Goodmans pricelist, April 1961. Prices, among other things, for the Audiom 90 and Midax horn.
Some pages from Goodmans speaker brochures - the Midax horn in 1958 and 1960. For more on the Midax, see this page, which will be updated again shortly. The connecting plugs, mentioned in the adverts, and used by Vox, were made by Belling Lee.
Goodmans brochure, 1958
Goodmans brochure, 1960
Material relating to AC50 speaker cabinets and the speakers used in them (Celestion, Fane, Goodmans) is being gathered together on this index page.
31st August (2)
Pages from a mid 1960s Fane brochure relevant to the AC50 - the 122 (specifically the 122/17), used in Super Twin cabs from 1965; and the 183, fitted to Foundation Bass cabs when Goodmans were not available.
Just for context, the front cover of the Goodmans pricelist - principally for the hifi market, but see the note under the Audiom speakers.
A page from the Goodmans retail pricelist, March 1964. The Audiom 91 has now superceded the Audiom 90. According to the Bank of England inflation calculator, £27 10 shillings would be around £500 in today's money. This was wrongly said to be the price of the Audiom 90 in the entry for 25th Aug. JMI presumably got its Audiom 91s at a substantial discount.
25th August (2)
AC50 serial number 1584, made by Triumph, last third of 1964, now registered here. Thanks to Larry for the pictures.
Below, a Goodmans flyer from 1962/63 (corr.), illustrating the new 18" Audiom 90, the first heavy duty bass speaker produced by a British manufacturer. The initial version was 6ohms and aimed principally at public address applications, though it was more often used for organ amplification. The 8ohm and 15ohm versions - the former used by Vox for the earliest Foundation Bass cabs (and a few in 1965) - came slightly later.
A chassis probably produced in February or March 1965 - pot codes "AM" = January 1965 - in a box (with serial number plate) that is some months later. Further pics here. Thanks to Dennis.
AC50 serial number 1004B has just come to light - single channel (2 inputs), copper panel, small thin-edged box. Thanks to Simon for the picture.
A good close-up of the label of one of the Fanes belonging to AC50 Super-Twin serial number 5533.
Model no. 122/17, 25 watts power handling, 15ohms. Serial numbers can be a good guide to the relative dates of cabinets. Note the Fane part no. 7470.
14th July (2)
The page on large-box AC50 (Super-Twin) cabs has been updated. Further material to be added shortly.
Currently on ebay, AC50 serial number 2787, needing some attention. The amp is one of a batch produced around March 1965 by Triumph with eyelet tagboards for the bias circuitry. Others are here.
A recently surfaced twin-channel amp in a small box added here - serial number 1311. The lowness of the number is simply a consequence of the boxing process: a new chassis from Triumph was put, at JMI, into a box, complete with serial number plate, that had been made a good number of weeks before. Thanks to Frank and Tom for details and pictures.
Click for a slightly larger image. Harrison's AC50 on stage at the Cinema Cyrano, Versailles, 15th January 1964. Note the Bulgin fuseholder on the back panel (one was also present on McCartney's AC80/100).
Also note the little bits of tape on the control panel marking the settings for the controls, and the cigarette about to burn the tolex.
A couple of new amps with serial numbers in the 6000s added on this page. Both have double pin corner protectors. The amp with the lowest serial number certainly to show these is serial no. 6471.
"Melody Maker" magazine, 5th October 1968 - the new Orange shop on New Compton Street. Part of the premises had formerly been owned by JMI. Two AC50s in stock. The Vox Essex bass amp must have been an import from the USA.
The Orange shop in the 1970s (?). Pic from this page.
No AC50, but one can just see a Vox Supreme middle left.
"Melody Maker" magazine, 27th July 1968. Small ad advertising a Vox 50 watt PA new in boxes.
Serial numbers for PA amps were part of the sequence for the guitar amps. Below, AC50 serial no. 02666, actually a metal-clad sloping-front PA.
A new page now started, bringing together dealer ads and small ads for Vox AC50s published in newspapers and magazines in the 1960s - click here. It's also accessible on the main index page for Vox promotional material.
25th May (2)
Melody Maker magazine, 14th August 1965. Probably a small-box Mark 1 AC50. Large box AC50s are considerably wider than T60 speaker cabinets and were never formally issued with them in the 1960s.
Left: Melody Maker newspaper, 17th April 1965, advert for the National Beat Contest. Right, Beat Instrumental magazine, March 1966. Ads for the AC50, 1965-1967, are being collected together here.
Judging by the ads in the back of Melody Maker magazine, Vox AC50s paired with Line Source speaker columns seem to have caught on as PA amps. There is also this short notice:
24th May (2)
From the small ads of Melody Maker magazine, 13th March 1965: "1964 (July) Vox AC 50 Amp. Bass Amplifier, £90". Given the date of purchase, evidently a small box AC50 Mark 1, either thin or thick edged.
Melody Maker magazine, 30th January 1965: a Vox A.C.50 Super Twin and Stand" for £184. This was the standard retail price at the time.
Melody Maker magazine, 2nd January 1965 [CORR]. Macari's Musical Exchange in Edgware (the first shop) also had a new one to sell. The two-year Hire-Purchase terms are noted.
A further amp with a serial number low in the 4000s - its plate being two-line - added here. Three-line plates come in around serial number 4150.
AC50 serial number 4094 now registered here. The amp is similar to no. 4083, immediately above it on the page. Thanks to Jerry for the pictures.
Continuing the theme of adverts, above, one first published in "Beat Instrumental" magazine, May 1966 - perhaps a sort of passing reference to the AC50's name in the U.S.A. in 1965: the "Royal Guardsman". By May 1966, however, sales of English valve amps had more or less come to an end.
Currently on Gumtree UK, serial number 1931. Valve rectified (Mark 2) and in good external order. Probably from late 1964. "AC50" is handstamped, the serial number machine-stamped.
Serial number 3619 (above) now registered here. The presence of the 0.05uf 800v grey Radiospares capacitor in the preamp by the choke indicates that this amp was made for export to the USA. Note also the original sticker "Taylor-Made Woodware" on the underside of the slider board. Thanks to Don for info and pictures.
AC50 serial number 3640, solid state rectified, pre-brimistor. From the third quarter of 1965. Pot codes "EM" = May 1965. Great condition. Thanks to Peter for the pictures. Further coverage on this page.
Some transformers from two AC50s: output from serial number 5369 (1966); and mains from a Dallas Arbiter amp (1975):
The two images above, the output transformer from serial number 5369 its the plain metal shroud lacking. The black-shrouded units were introduced shortly after this amp had been produced.
The mains transformer from a Dallas Arbiter amp.
A picture page now set up on AC50 serial number 3339, supplied by Servaas Muziekhandel in The Hague with a UL760 cab. Thanks to Philippe.
Below, 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 has been reconed.
Pulsonic code of the original cone in the right hand speaker.
Above, a detail of the metal dust-cap, which has a black rubber trim strip around its edge.
14th April (2)
Further pictures of AC50 serial number 1503, valve rectified, early style large box, added here.
Above, the first advert for the large box AC50 published by Vox in "Beat Instrumental" magazine, August 1965.
"Beat Instrumental" magazine, November 1965: advert for the large box AC50 Super Twin, the amp slightly squint on the trolley.
Note that the large box AC50 had already been represented, however, in UK and US brochures published in late 1964 and early 1965. See this page for examples.
A page from a German brochure, printed in September 1967 and circulated in 1968. 2628 deutsche marks (for the AC50 super twin) was equivalent to around £260 - £4300 or so in today's money (according to the Bank of England inflation calculator). The amp alone was 1188 deutsche marks = £110 in 1967 = £1800 today.
Page 4, which advertises two 7-series amps - the UL710 and UL730 - is posted here.
Above, excerpts from the British retail pricelist of April 1967. Prices in Germany were around 50% more than in the UK.
AC50 serial number 1503 from the last third of 1964. Note the early box with cut-outs in the baffle. The corner protectors are later replacements for the original single pin protectors, now gone. Further pictures to follow. Thanks to Peter.
6th April (2)
"Formula 1" (from the West Midlands) pictured in late 1964 with a small-box (presumably diamond input) Foundation Bass set, similar to the one with Johnny Hallyday's band, below.
Two shots of Johnny Hallyday and band from Getty Images, the first from 1967, the second 1966. Great views of the brown-fronted diamond-input amp and Foundation Bass cab.
"Vox Sound Equipment Limited" AC50 serial no. 1081, the highest number to have surfaced so far. The cab is a Jennings Electronic Industries B1 (bass, 1 x 18"), from 1969-1972. Further pictures here. Thanks to Roland.
Pentangle on stage, Copenhagen, September 1969, with two AC50s - one with new-style logo, one old. Pictures from Getty Images.