List of updates / new info. on Vox solid state amps (1967-1972)
Updates for April 2017
26th April (2)
A detail from Gary Hurst's account of the British Musical Instrument Trade Fair at the Russell Hotel, 1968, the extract again from Beat Instrumental, Oct. 1968.
The Supreme is £281 (against £271 and 19 shillings in April 1967), and the Super Foundation Bass £211 (against £204 and 15 shillings).
Perhaps more interestingly, amps and cabs are now available separately.
Above, a detail from the Vox advert in "Beat Instrumental", no. 66, October 1968, the company now presenting itself as "Vox Sound Equipment Ltd".
The date of these ads (and what they depict) is often revealing. Too often they are used in books and on web pages simply as a sort of decoration, no date or source acknowledged.
Note from "Beat Instrumental", no. 57, January 1968. Posted here simply to chart the persistence in 1968 of the name "Jennings Musical Industries". At some point a couple of months later, the company was reformulated as "Vox Sound Equipment Ltd".
In late 1967, Royston Industries, the umbrella company that controlled and owned JMI, began to fail, thanks in no small part to its unsuccessful venture into the field of avionics. The receiver was called in in December 1967. In February 1968 various subsiduaries were sold off.
Above, Jethro Tull, Hyde Park, 29 June 1968. Behind the tall man on stage at left (with his elbow out), a Supreme - probably Marc Bolan's, as the other participants were T-Rex, Pink Floyd and Roy Harper.
Dave Dee, Dozy, Beaky, Mick and Tich with three Supremes and a Super Foundation Bass on the parade ground of the 1st Battalion of the Parachute Regiment, 7th November 1968.
22nd April (3)
A preliminary page of "Beat Instrumental" adverts now here.
22nd April (2)
Page from "Beat Instrumental" magazine, no. 56, December 1967. Still Jennings Musical Industries.
Page from "Beat Instrumental" magazine, no. 51, July 1967. Advert coinciding with The Monkees' stint at the Empire Pool, Wembley, 1st and 2nd July. In the pictures that have surfaced to date, no equipment is discernible on stage, however.
The various ads from "Beat Instrumental" will be gathered together chronologically on a new page.
One of Gary Hurst's answers from the Q&A page of "Beat Instrumental", no. 56, December 1967. The Conqueror is quoted at 162 guineas.
In effect, no change from the price-list of April 1967 - £170 and 2 shillings. A guinea was one pound and one shilling. There were 20 shillings to the pound.
Extracts from "Beat Instrumental" magazine, no. 51, July 1967. Pete Quaife and Bill Wyman signalled as users of Super Foundation Bass amps.
An old pic of an early Supreme with a black control panel - either very early, ie. in the first forty (ST.1001-ST.1040), or around ST.1100.
Advert from "Beat Instrumental", no. 52, August 1967. The earliest ad to show a standard production (rather than pre-production) Supreme. The illustrated solid state brochures from 1967 all show pre-production amps.
Short piece from "Beat Instrumental", no. 50, June 1967. Click as ever for a larger and sharper image. Manfred Mann - really in relation to the entry below for 17th April. Note the last sentence - "My Leslie goes through one of the new, large Vox amps".
The Isle of Wight festival, 1970. An array of Supremes and Super Foundation Basses for Tony Joe White, Lighthouse and Chicago.
For further pics of the concert, taken by people attending, see the links in the middle of this page - site pix 1-35.
17th April (2)
This is the pre-production amp with which he is pictured in photos from 1970 - slivers below. The speaker socket is at left on the back, and the mains socket at right. In standard production amps the speaker socket is at right, and the mains socket in the centre.
Pics from 1970. Note the position of the footswitch socket (and the orientation of the DIN plug), and the numbers next to the inputs on the top panel. For further pre-production amps, see this page.
The page on bands with Supremes now updated. Further material to follow - the page may have to be divided if it grows too large.
The serial number plate and capacitors from Supreme 2629. 2629 is close to the end of production. Its red CCL caps have the date code "D71" = April 1971. The power section has the "Birch Stolec" inspection stamp.
Vox Sound Ltd. staggered on until 1973, but the production of guitar and bass amps - Defiant, Foundation Bass, Supreme, and Super Foundation Bass - ceased in 1972. No doubt they were a really hard sell.
The Conqueror and Dynamic Bass were phased out in 1970.
15th April (4)
A page on the MRB circuits now roughed out here.
The six-position MRB circuit was introduced in 1969. It can be seen in VSEL Supreme no. 2248. the latest dateable component in the preamp of Supreme no. 2248 is a mustard cap. A9N = first quarter of '69.
15th April (3)
The pages on Dynamic Basses now updated.
15th April (2)
Better shots from "One Plus One". The last shows an unknown solid state amp - far right - at the back of the studio. The Supreme cab evidently had Goodmans speakers with black caps and silver frames - note the JMI labels
Below, a detail of the standard JMI mid-range boost circuit, along with a drawn representation of how the circuit is arranged in the guitar amps.
Everything but the inductor and the MRB select switch sits underneath the top of the control panel. Lines in purple show the circuit without mid-range boost. Orange/brown shows how the MRB feeds in.
The signal feeds into the treble pot from the treble/distortion circuit board, from there it goes both into the bass network and on to the leg of the 1uf capacitor. It then passes across the inductor, into the 10K resistor, the 0.033uf capacitor and finally to the volume pot.
Pressing the MRB switch puts the inductor in parallel with the MRB capacitors, activating the boost. The signal is mixed with the "clean" signal through the 0.01uf (10,000pf) capacitor on the tagstrip.
14th April (2)
In relation to the flyer below, the power sections of the English solid state amps were in the main Vox / Burndept designs. A few elements were borrowed, however, from Thomas Organ circuits. The preamps were more heavily indebted, especially the MRB and tremolo.
The design of the power amp remained consistent until end of production. The tone circuit of the preamp changed twice though - most obviously with Vox Sound Ltd schematic OS184 (treble) and OS185 (bass).
The MRB became six position instead of three. Notes on these changes will be provided soon.
Just to say that early Supremes are much louder than later amps - considerably louder in fact. VSL-made units are, as Dave Petersen noted, really only on a par with AC50s.
Extolling the solid state line - details from a flyer from mid 1967. The "reversing the amplifier on its stand" was presumably aimed squarely at keyboardists.
13th April (3)
Notices from "Beat Instrumental" magazine - February and March 1967 (nos 46 and 47) - relating to the old Vox/Jennings shop at 100 Charing Cross Road.
Interesting to see that Wedeles bought a "huge pile of spare parts from Jennings". Later on in the March issue, it's noted that Gary Hurst of Tone Bender fame moved into the shop with the Macaris.
13th April (2)
Below, probably the first time the new solid state amps had been seen at a major event in Britain:
Cream at the Daily Express "Record Star Show", Wembley, 16th April 1967. The Super Foundation Bass used by Jack Bruce is just visible at the bottom of the second pic.
Below, grabs from the film "One Plus One" by Jean-Luc Godard showing the Stones honing, for the camera, "Sympathy for the Devil" in May 1968 at Olympic Studios.
The Foundation Bass is used throughout the sequences, the Supreme not that much - or maybe the bulbs of the indicator lamps on front were removed for some reason. Both amps are evidently JMIs. The blue tags on the Supreme suggest it was brand new. It certainly looks so.
12th April (3)
Not all Supremes are made equal.
In the foreground, an early one (1058). Behind it an early VSEL. The VSEL box is 1/2" wider. It is also 1/4" taller.
Why the difference? The sides and bottoms of early boxes are 1/2" thick. Sides and bottoms of VSEL boxes are 3/4" thick.
12th April (2)
"CCL", the company that made the red filter capacitors present in most JMI-made solid state amps, is "Cambridge Capacitors Ltd", taken over by Pye, also based in Cambridge, in 1970. It became independent again later.
Not sure that this has any discernible significance - "VIB" stamped on the preamp of an early-ish Foundation Bass. Can't think what it means, handsome lettering though.
11th April (2)
Marc Bolan with a Supreme, 1st January 1970. Pic from Getty Images.
T-Rex at the Weeley Festival, 27th August 1971, a Supreme at right in background. Pic. as above from Getty Images.
Some notes on Vox Travellers:
The part number for the mains transformer of the Traveller is 67928. As mentioned earlier, the company that made the transformers for the solid state range for Vox/Burndept also made black-topped units for the AC100 and AC50. The part numbers of the former were 66775 and 66776.
The mains transformer of Traveller no. 1019 has the maker's logo (orbit of an electron) and name "Allen". Was this the compnay that made the units?
If anyone knows more about this company do let me know. Stickers marked "Allen" appear on the transformers of early 1970s Simms Watt and Sound City amps, but no logo, and a completely different format of part code (for instance, "AC1336").
A late Traveller (no serial number) has RCA 40312 power transistors with the code "6E" = May 1966. Clearly Vox/Burndept bought a large batch that were not used up quickly. Inside the amp, however, the RCA 40360 preamp transistors have the code "8B" = February 1968.
9th April (3)
Pics of a Virtuoso without reverb added here. Thanks to Aart.
9th April (2)
Picking up from the entry earlier today:
Above, the driver transistor of Supreme no. 1258. The date code is "8A" = January 1968.
Output transistors "7M" = December 1967; CCL filter caps "G7" and "K7" = July and November 1967; CCL bias caps "I7" = September 1967.
The latest dated component in the preamp is a mustard cap "C7N" = third quarter of 1967.
Supreme no. 1258 was presumably ready for shipping or sale therefore in February 1968 along with other batches of amps. Whether 1258 was the latest of its batch or the earliest is unknown at present.
Above, the serial number of 1258's power section: "P10A S/No. 01434". Note that its format is different from the one found in early JMI Supremes.
When VSEL came into being it evidently took over a good many fully-assembled and part-assembled JMI amps. Whether in its early days amps with JMI plates, rather than its own, were sent out for sale remains to be seen. It certainly seems possible.
So far we have very few component date codes from late JMI and early VSEL units to go on.
SUPREMES: Jim Elyea records in his book (p. 539) a JMI Supreme with the serial number 1503. This is evidently an error, passed to him by a correspondent. No JMI Supremes with serial numbers in the 1300s or 1400s have come to light. The highest Super Foundation Bass, which had a power section in common with the Supreme, is 1280.
It seems likely therefore that around 300 SFBs were made in the JMI period, along with 300 Supremes. The date codes of Supreme no. 1258 are the closest we can get for the time being to the crossover into VSEL.
As indicated further down this page, no. 1258 has RCA power transistors with the code "7M" = December 1967. Other codes will be posted later today.
VSEL: a couple of things to note. New preamp and power amp chassis do not have machine-stamped numbers as they do in the JMI period:
Above, the section serial numbers from Supreme no. 1058. "100W PA SER. NO. 01045" - the "0" did not stamp properly. And "PRE/AMP.T SER. No. 01782". ".T" indicates "Treble", i.e. for a guitar amp. New VSEL units do not have these stampings.
VSEL serial number plates are by contrast hand-stamped. What happened to the stamping machine used for JMI plates? The amps were still made at the Burndept factory after all.
The pages on Super Foundation Basses now tidied up. Some more details and amps to be added soon.
Some more about serial numbers, dates, and date codes, taking the guitar amps, specifically the Supreme, as a starting point:
PREAMPS - these were made in batches for the Virtuoso, Conqueror, Defiant and Supreme. The earliest had yellow Lemco caps, which were superceded in the course of production by blue Phillips. When a Supreme was to be assembled, a preamp was grabbed from the pile.
POWER AMPS - made in batches for the Supreme and Super Foundation Bass. Unique components (ie. those not used in other solid state amps) were the transformers, filter capacitors, a range of Welwyn cement resistors, and sundry other parts. Relatively few Supreme and SFB power sections were produced at first.
In terms of sequence, there is no sense in which Supreme no. 1055, or at least its power section, was made on a Wednesday and number 1056 on a Thursday. But amps were assembled in small batches, week by week.
And one can tell by the component date codes that procedure at Burndept was extremely orderly.
What goes for the Supreme also goes for other amps.
If anyone has an amp open for repair, or feels like investigating date codes, do let me know - would be much appreciated.
3rd April (2)
A really strange one. An "ESE Custom 200 Bass" built by Eric Snowball, a former employee of Vox, using various stray parts. The power section is a modded Supreme, and the box a sort of variant Supreme box. There is a large opening at front, bounded by white piping, into which ES fitted the preamp and blanking pieces.
Note the long single vent at top fitted with a metal grille, as in early amps. The string round the box, which may have been fitted by ES (it is a bit bodged), is silver, however.
The back panel, identical in almost all respects to a standard Supreme back (pictured above it), has a central wooden section at top (where the metal grille is).
This is certainly not a box for a V100. If anyone has seen anything similar either with an original Vox amp in, or with another, do let me know.
Above, the shop plate of the VSEL Supreme from Denmark - marked "A1". The serial number plate has gone unfortunately, but see the analogous case of the Defiant, below. Date codes of components in the Supreme indicate it was produced, and perhaps exported, in the second quarter of 1969.
Continuing the theme of transformers begun yesterday, the two units found in the Conqueror are:
Mains transformer: 13581.
Driver transformer: 13507A
So for the "Super Twin" guitar and bass amps (i.e. those with separate amp and speaker sections), the roster of parts is:
|Mains TR||Driver TR|
What goes for the Conqueror goes for the Dynamic Bass; the Defiant = the Foundation Bass; and the Supreme = Super Foundation Bass. Further info will gathered together on a forthcoming page.
1st April (2)
In reference to the preceding entry on the Super Foundation Bass, the stamped code on an early Defiant:
The mains transformer of Defiant no. 1031 - code 13717, JRB. Not quite sure what the "JRB" signifies - a secondary part code? That might make sense in relation to Super Foundation Basses (and Supremes) having "JSB".
An earlyish Super Foundation Bass with a very brown panel:
Thirty odd years in the West Country, it came without a back panel (and thus no serial number plate).
Marked on the mains transformer, the code - 13759 - and three letters stamped in white, "JSB" or "J58"?
The driver transformer is - 13478A.
The same transformers were used in the Supreme. The maker is at present unknown, but the company was the same one that produced the black-topped transformers for AC100s. These too have five digit codes, and occasionally letters stamped in white.
Various ideas have been floated - that the maker in question was "Albion Transformers", which at one time had made transformers for the AC30, or a manufacturer that Geoff Johnson of Triumph had found. Both unlikely.
The company must have been found by Burndept, which produced the AC100s with black-topped units and which developed the solid state line.
Back briefly to the Super Foundation Bass: the latest date code is March 1967 - one of the RCA transistors:
The 2N3055s have been replaced, but the 2N3054s remain. The code is 7C = March 1967.