Vox AC30: beginnings
The AC2/30 - 4 or 6 inputs
Two EL34 valves.
"Melody Maker" magazine, 8th March, 1958. Bulletin no. 3 of the JMI Electronics Division.
Produced in late 1957 - Spring 1958. The amp came in two varieties: the standard model with four inputs, lacking Vibravox; the other with six inputs, Vibravox built in, the additional two inputs being for the Vibravox channel. Descriptions in the adverts (see below) occasionally conflate the two.
The speaker was a 15ohm 12" unit - probably a Goodmans Audiom 60. See the "Melody Maker" advert for 22nd February 1958, below.
The amplifier's control panel was black and the knobs white.The cabinet had a split front with diamond grille cloth fixed horizontally. There was a cut-out on top of the cabinet for the control panel and a vent to dissipate heat from the valves. A solid luggage handle was fixed to the cabinet's right-hand side.
The AC2/30 was a sort of multi-purpose amplifier - aimed at accordionists, lap-steel players, and guitarists. It was taken up by a number of famous musicians: Jack Emblow and Henry Krein were both pictured with one, Bill Kent, and Bert Weedon (no pictures of the latter at present). Dick Denney is also said to have used one at the Embassy Court ballroom in Welling.
Judging by the advert above, Jennings was evidently proud of the built-in vibrato/tremelo - "gives such a startling effect that tape recordings have been made and will be sent on request...". The circuit diagram for the AC2/30 is OS/003.
"Melody Maker" magazine, 16th November, 1957, and detail. 55 gns for the standard model, 62 gns for the model with vibrato (vibravox). The logo takes this form on the amp illustrated in the "Accordion Times" advert, December 1957, page 31, below.
"Accordion Times", December 1957, page 24. The logo is of the same form in the advert in "Melody Maker", 11th Jan. 1957, below.
"Accordion Times", December 1957, page 31. As in the "Melody Maker" illustration above, "VOX" in large letters diagonally across the upper panel. The four controls indicate the amp is a standard model - two volumes, one bass, one treble.
"Melody Maker" magazine, 11th January, 1958. Bulletin no. 1 of the JMI Electronics Division. The AC2/30 is last in the row of thumbnail sketches.
"Melody Maker" magazine, 22nd February, 1958. The prices are still 55 gns (standard), 62 gns (vibrato).
"Accordion Times" magazine, March 1958.
"Accordion Times" magazine, February 1959. The Francis Wright Quintet.
"Melody Maker" magazine, 12th April, 1958, and detail.
Raggett's Hall, Maidstone, 1958. The "VOX" logo has gone, but the small plaque underneath - "Jennings" (?) - remains.
For further pictures of the AC2/30 in use on stage (venues in Kent) in 1957 and 1958, see this page. It has been ventured that "only a handful were made". This may need to be revised as at least 5 different ones are captured in contemporary photographs.
MELODY MAKER, February 1958 (above): VOX AC2 AMPLIFIER 55 gns. A 30-watt output at 15 ohms, A.C. mains operation Hi-Fi amplifier, fitted with three input sockets: (a) for crystal mikes, (b) for ribbon-moving coil mikes, (c) for gramophone pick-ups, radio tuner units and high level signal inputs. There are two volume controls for inputs (a) and (b), and one volume control for input (c), in addition to separate bass and treble controls. (Fitted with internal vibrato. 62 gns.)
3 inputs, 3 volume controls, 2 tone controls (bass and treble). Note that the amplifier in the descriptions below has PAIRS of input sockets. There is no explicit mention above of guitar or bass.
ACCORDION TIMES, March 1958 (above): "Vox Hi-fi Amplifier AC2/30 has 30-watt output; A.C. mains, 12in. heavy-duty speaker; three pairs of input sockets, each with its own volume control, also two separate overall bass and treble controls. Standard model: 62 gns. Fitted with internal vibrato: 70gns."
The 6 inputs, 3 volume controls, and 2 overall tone controls (bass and treble) evidently describe the Vibravox model. The vibravox circuit presumably required a further control on the control panel, bringing the total to 7.
Detail of the Vibravox from "Accordion Times", March, 1959.
JENNINGS CATALOGUE, 1958: "Vox Hi-fi Amplifier AC2/30. 30-watt; A.C. mains (200v to 250v), with four high-inpedance input sockets - two for use with crystal mikes, guitars, electro-bass, accordions etc., and two for use with guitar, electro-bass, radio-tuner units, radiograms and recorders. There is a volume control for both pairs of inputs, also two separate bass and treble controls. The amplifier is housed in a robust case fitted with a 12-in. heavy duty loudspeaker and also, if required, a VIBRAVOX unit."
4 inputs, 2 volume controls, 2 tone controls (bass and treble) describe the standard model.
The AC/30 - 4 inputs (Summer 1959 - Early 1960)
Two EL34 valves.
An early advert for the AC/30
The AC30 in a new format: its cabinet and styling borrowed from the AC1/15, which had remained in production throughout 1958 and 1959. Tremolo and Vibrato come built in. There are no longer "standard" and "vibrato" models.
The amplifier chassis comprised of two parts: the preamp, with controls, at the top of the cabinet; the power section fixed at the foot. This was the standard arrangement of the day, employed also by Selmer and other manufacturers.
The AC/30 preamp section, which contained all the valves except the GZ34 rectifier, was initially a modified AC1/15 chassis. In early 1960 a dedicated AC/30 preamp was designed and put into production.
During this period, i.e. 1959-1960, Denney evidently worked to turn the AC/30 into a single chassis amplifier, using EL34s at first, then four EL84s. This new design, or rather format, was to become the AC30 Twin.
The schematic of the single speaker dual-chassis AC/30 amplifier is OS/007, dated 1st January 1960. Certain elements changed (or were variable) as production proceeded.
Back boards were normally brown or black perforated fiberboard.
On the back of serial number 4052 the legends stencilled in white are: "Made in England, Jennings Musical Industries Ltd., Unity Works – Dartford – Kent – England". At the bottom, centre: “Warning, Disconnect Mains Plug Before Removing Back Cover". On the left side: "For AC Mains Only". Right-hand side: "Check Voltage Setting On Back Of Chassis". At the bottom of the panel on the left-hand side:"Serial No." though no number is supplied.
The details above come from John Teagle's interesting piece published in "Vintage Guitar " magazine, May 1998 - available here.
The power chassis of the new AC/30 was housed at the foot of the cabinet, the preamp at the top. The complement of valves was: POWER SECTION - GZ34 rectifier, and two EL34s. PREAMP - three ECC83s and one ECC81 (the phase inverter).
Serial number 4052's speaker is a Rola G12. The original cover, which still survives with the amplifier, is green with tan piping.
The note in the "Accordion Times", June 1959 (below) that "a 30-watt model CAN be supplied..." indicates the amplifier's newness at that point.
The new AC/30 - "Accordion Times" magazine, June 1959.
"Accordion Times" magazine, July 1959. The amplifier is not illustrated but described briefly: "4 inputs, 30 watts output, 70 guineas".
"Melody Maker" magazine, 31st October, 1959 - new guitars, including the Electronica Oval-Basso (the small image showing it in profile). The amplifier priced at 70gns is the new AC/30. This advert first appears on 10th October, 1959 (though lacking the profile representation of the electro-bass).
"Melody Maker" magazine, 14th November, 1959. A growing roster of artists, now including Cliff Richard, Marty Wilde, and the John Barry Seven. The AC30 - 30 watt output, 70 guineas.
"Melody Maker" magazine, 28th November, 1959, a detail from a Boosey and Hawkes advert. Dave Goldberg, noted as a Vox user in the ad. above this one, with what may be an AC/30.
"Accordion Times" magazine, April 1960, the AC/30 (not described explicitly) being the amplifier priced at 70 guineas. Note the new style of Vibravox with an inset black control panel.
"Melody Maker" magazine, 30th April, 1960. The AC/30 now 79 gns. There is also a bass version at 85 gns.
"Accordion Times", May 1960. The AC1/15 at 65 gns, the AC/30 at 79 gns. The amplifier at 100 gns is the new AC30/4 twin - see this page.
Detail from above.
"Banjo, Mandolin and Guitar Magazine", October 1960, still the AC/30 in its single speaker format. Note the logo/emblem lower left on the front grille, as in the illustration at the top of this section. Picture from this great blog.
in early 1960 the price of the AC/30 had gone up to 79 guineas.
Single speaker amplifiers.
At present, three amplifiers with serial numbers are known: 4041, 4052 and 4076, the sequence presumably beginning at 4000 or 4001.
Perhaps around 150 were made. Whether the sequence runs up to or into that of the TV front amplifiers is unknown at present.