List of updates / new info. on Vox solid state amps (1967-1972)

Updates for the second half of March 2017

31st March

Above, stills from the interviews slipped into the film of Cream's Farewell Concert at the Albert Hall, 1969, a Vox Supreme cab in its cover visible in the dressing room with Clapton and on stage (for the rehearsals?) behind Ginger Baker.

I have a recollection of spotting it years ago (on the film) during the concert itself, far out on the wings of the stage, but nothing doing in the youtube copies.

30th March

A great pic taken in Eric Snowball's shop in Maidstone, ESE Music, in the 1970s. A couple of SS PA amps along with a Midas, a Foundation Bass, and a Gyrotone?

29th March

Making progress little by little sifting through the backlog of pictures and info. Four later Defiants today - one VSEL, the others VSL.

Old pics of Defiant numbers 2119, 2760, 2764 and 2814 posted on this page, the last close to end of production.

28th March

Pics of Defiant no. 2258, designated "B1" for the Danish market, added here.

Defiant no. 2119 now on the page linked above.

27th March

The page on production is in the process of being recast - some caveats concerning pics that were printed a few years ago are to be found at the foot of that page. Conqueror no. 1059 added here.

26th March (2)

Conqueror 2029, early Vox Sound Equipment Ltd. Note the hand-stamped serial number plate (standard early VSEL practice). Later plates are machine stamped.

Note that the speakers are either Goodmans or Celestion ceramics, a large speaker sticker (JMI) for the large dustcap.

A number of early Conqueror cabs have lost their original drivers, so it's difficult to say how common Goodmans or Celestion ceramics might have been. The next earliest VSEL cab, accompanying Conqueror no. 2181, has Celestion alnico T1088s, which were standard during the JMI period.

26th March

A new page started on Defiant no. 1031 with photos and details of component date codes, the latest of which is February 1967.

25th March (3)

A detail of one of the top preamp fixing screws inside an early box - this from Defiant 1031. Screw and nut keep the washer tight against the lip of the preamp assembly, preventing it from slipping down inside the case. These screws, which slot through externally from just behind the front corner protectors, were phased out by summer 1967.

The fixing point on the outside of the box.

What may have prompted the inclusion of this arrangement was the experience of the Super Beatle amp in the US. Its internal preamp fixings were not strong - and there was nothing to stop the whole assembly slipping down when they gave out.

As it turns out, the JMI internal fixings were good and firm, so there was no real need for the additional screws - which is presumably why the pair on top of the box were dispensed with.

Two internal fixing points of Defiant no. 1031. Top of the box is at right.

The nuts of the internal preamp fixings are a devil to get off and back on again. The best aid to getting them out is a 2BA nut "spinner" - 2BA being the size of imperial screw. "BA" = British Association.

Above, a Radio Spares 2BA spinner. These regularly pop up on ebay.

25th March (2)

Recent info. from Denmark:

A Defiant in excellent condition - note the designation "B1". The Supreme for Denmark was "A1" and the Conqueror "C1" - see this example, for instance. Thanks to Morten for the pic. Further shots of the amp and cab will be posted soon.

Above, a Supreme also supplied in Denmark by the Alfred Christensen company - its sticker is on the back panel of the power section, over the hole left when the voltage selector was removed - to accord with Danish (and Swedish) regulations. The owner kindly tells me that the amp is designated "A1" on the serial number plate.

The Alfred Christensen Musikhandel went out of business sadly in 2012.

25th March

In ref. to the new page posted yesterday, some later dated components from the Vox Sound Ltd period - 1970-1973.

Defiant no. 2423, "Vox Sound Ltd" on the serial number plate, but "Vox Sound Equipment Ltd" control panel, so assembled in late 1969. Above, a shot of the CCL capacitor with date code "D9" = April 1969. The blue Plessey caps have "C-9" which probably means March 1969 - either that or third quarter of 1969. If anyone has a reliable source for Plessey codes, do let me know.

Vox Foundation Bass no. 2813, close to the end of the run. RCA transistor with code "2D" = April 1972.

Heat sinks from a broken Vox solid state PA amp. The RCA transistor have codes "3H" = August 1973. These amps were made after production of the guitar and bass amps had stopped.

Vox Supreme no. 2510, Vox Sound Ltd. Mustard capacitor with code A0W = first quarter of 1970, Wembley factory. Other obeservable mustard caps have "D9", no factory designation = last quarter of 1969. This amp was paired - perhaps at the factory, though there is no proof absolute - with a Vox Companion 4x12" cab with Celestion T1925s dated "HE" = August 1972.

Probably in the early 1970s it took a good while for stock to sell. Vox Sound Ltd evidently struggled.

24th March

A new page on the date codes of components in Vox solid state amps now taking shape here.

23rd March

The page on later Defiants now tidied up - it will probably be separated out into two pages soon.

21st March

The page on JMI Defiants has now been divided into two. Early ones are here, and later ones here. Additions to follow.

19th March (2)

RCA transistors also have date codes, the system being similar to the one adopted by CCL capacitors. Number = year, Letter = month.

However, as the sequence of letters on the RCA devices goes up to "M", it seems that "I" was omitted: A-H = January to August, J-M = September to December. Lemco capacitors also follow this system.

Supreme no. 1065. The code on the 2N3055 reads "6K" - click on the image to enlarge. "6K" = October 1966.

Supreme no. 1258. The code reads "7M" = December 1967.

The picture immediately above indicates that complete JMI Supremes were still being finished off in early 1968, doubtless under the auspices of the new company, Vox Sound Equipment Ltd.

19th March

Below, a short digest of the observable date codes of the red CCL capacitors in *power sections*. Some riders: (A) sometimes only one cap. is observable in the pics. (B) caps with old codes could evidently remain unused for some time (Conqueror 1189) (C) Preamps and Power sections were brought together at the end of the assembly process - ie. preamps might have caps with a slightly different range of dates.

The table records the latest *observable* date in the power section. It may need adjusting following closer scrutiny of the relevant amps.


1046 A7 Jan. 1967
early_01 L6 Dec. 1966
1189 K6 Nov. 1966


1031 L6 Dec. 1966
2032 F7 June. 1967


1058 L6 Dec. 1966
1065 K6 Nov. 1966
1087 D6 Apr. 1966
1094 B7 Feb. 1967
1110 G7 July 1967
1121 G7 July 1967
1258 I7 Sept. 1967


1090 G7 July 1967

Date codes on grey cement Welwyn capacitors, and on the little yellow Lemco capacitors in the solid state preamps are comprised of two letters: the first the year, the second the month.

First letter X = 1966, Y = 1967. Second letter is the month, A-L.

Above, a detail from the preamp of Supreme no. 1094. Visible a CCL capacitor, code B7 = Feb. 1967; and two yellow Lemco caps, code YB = Feb. 1967 too.

Next week, the entire dated component complement of an early Conqueror or Supreme will be charted and posted.

17th March (4)

The date codes on the red CCL filter capacitors used throughout the solid state range sometimes provide useful "earliest possible dates" for the production of an amp.

The example above is from Supreme no. 1058. The date code is one letter and one number at the end of the printed sequence - "L6" in this case. L = December, 6 = 1966.

The series of months begins at A for January, the number is always the year.

Naturally, capacitors were bought in batches which lasted some time, so the codes are not telling, in terms of the potential date of manufacture of an amp, in every case. But now and again they are exceptionally useful.

Above, Supreme no. 1110. The codes on the caps are "G7", which indicates that this amp must have been made after July 1967.

17th March (3)

A line to draw attention to the date codes on the bias resistors from Supreme no. 1087, pictured immediately below: "XL". X = 1966, L = December.

17th March (2)

The disappearance / non-survival of early Supremes: - we have early Conquerors and Defiants; and a reasonable spread of early Super Foundation basses, which have a power section in common with Supremes; but very few early Supremes themselves have so far come to light.

This could of course simply be chance - either of survival itself, or perhaps the way in which info and pictures have emerged.

Alternatively, it is possible that batches of unreliable early power transistors caused at least a number of early amps to self-destruct. The failure of transistors would also take out speakers in speaker cabs.

Above, the bias boards of serial no. 1087, partially burned away from the heat generated by the 6W Welwyn cement resistors.

Thermal runaway - the process by which greater and greater amounts of current are drawn through a transistor (generating greater and greater amounts of heat) - could easily result in a power section's demise. The cause: internal flaws in the transistor itself, or a poorly set up bias.

There are - somewhere - reports that the Stones' Supremes on the European tour encountered problems. But this should not be taken as fact until a reliable reference turns up.

17th March

Above, a snippet from "Beat Instrumental", vol. 47, March 1967, p.25, posted at the foot of this page a little while ago. Clearly the moment that Keith and Brian acquired their Vox Supremes and Bill his Super Foundation Bass. It may be that the invitation / trip was indeed primarily "to try out some new electronic effects". They came away at any rate with new amps to use on the European tour of Spring 1967.

"Beat Instrumental", vol. 48, April 1967, p.24. Within a month of the Stones' tour ending, the amps were evidently on sale to the general public. Note that 120W is still quoted, the output cited in the JMI advert for the un-named Supreme from Jan. 1967, featuring Tony Hicks - posted on this page. The price given in the snippet above - £252 - is that of the AC100, however. Below the official list of April 1967.

The official price list of April 1967.

Just to note: the wah had actually been developed - by the Thomas Organ Co. (the distributors of Vox in the US) - long before JMI came to advertise it. The account is given in "Vox Story", Dick Denney and Dave Peterson, 1993.

Above, the official list of April '67, giving the price of the Vox wah as £16 and 10 shillings, in today's money around £280!

The first JMI advert for the Wah Wah, from "Beat Instrumental", vol. 49, May 1967. Nothing about the solid state amps in the issue though.

16th March

A new page started on tilt-back trolley Supremes, gathering some of the details and info from this page.

15th March

Above, shots of the sort of fixing once fitted to the cab that accompanied Supreme no. 1094, pictured below, 13th March (3).

The flat of the bar is fixed to the inside of the cab with four screws in trapezoid formation, and the pivot screw, attached to the bar with a hexagonal nut, protrudes through the hole in the cab's side. It is not clear how the two pivot fixings pictured above came to be united with the T60 and repro trolley.

14th March (3)

The new page on the early Conqueror pictured below will be populated soon.

14th March (2)

Two more pictures from Warsaw, 13th April, 1967 - last for the time being:

Keith backstage, sitting on his Supreme cab, which is on its side. He is at the top - the amp is near what should be the bottom. Note the chalk-mark of the person who signed the cab off. The second pic. shows that his cab had the same ceramic Celestions as Brian's - see yesterday's entry.

14th March

Just to highlight the friction caused against the sides of the cab by the upper section of the tilt-back frame: - Supreme serial number 2312, for a long time in northern Germany, now in the USA. The cab in yesterday's entry was luckier, however.

A late tilt-back stand - still three pieces that slot together (not one piece as I originally thought, one can see where the two upper sections join). The casters are evidently replacements. A couple of amps survive with their original late stands. See Supreme no. 2376 on this page. The other has yet to be posted.

13th March (3)

Above, three quick details of the JMI tilt-back cab that came with Supreme no. 1094. Note the hole for the pivot screw relatively high up on the side of the cab. Pivots for full trolleys were positioned equi-distant from top and bottom. Another JMI tilt-back cab is pictured below - entry for 8th March.

Inside the cab, the outline of the plates on either side that held the pivot screws in place. The fixing screws for the plates remain though the plates themselves have gone.

When the pic of a couple of original plates comes to hand, I will post it here.

The cab pictured above is immensely heavy - thanks in no small part to the cast iron frames of the Goodmans drivers. A pretty top-heavy entity with the Supreme amp on top.

13th March (2)

Click, as ever, for a larger image. Mick Jagger on stage with Brian Jones's Supreme, 13th April, 1967. At last an almost complete view of the back. The cabs and amps were presumably issued to the band in mid March 1967, ie. before the tour began. Remember that pre-production amps were still being signed off in January. See this page.

Note the strange orientation of the labels on the speakers in the lower compartment. The cab pictured below - entry for 25th Feb. (4) - presents the normal arrangement.

13th March (1)

Probably well to put this up here:

The pic. (most likely from an issue of "The Beatles Book") shows the two metal vents on the top of one of the Conquerors present on stage during the recording of the promo video of The Beatles' "Hello Goodbye". A closeup of John's amp showing the "Conqueror" runner on front is below, 19th Feb. Frank Carvalho knew these amps were Conquerors yonks ago - see his site. There is brief comment on this page, and at the foot of this too. It seems well worth repeating these facts. Quite where the idea that these amps were Defiants came from heaven only knows - perhaps just a wrong guess that got picked up and repeated.

12th March

Really in reference to yesterday's entry, two shots of the early Conqueror with covers:

Below, a publicity shot of the "Spacemen 3" with a Selmer Compact 30 and what is said to be a Supreme, though one never sees the identifying runner in shots from this photo session:

The Spacemen 3 with Vox Supreme

11th March

All the pages on Conquerors have now been updated and should work well on mobile devices. There are some new amps yet to add - those will be posted later this weekend.

One thing that has emerged from looking again at the spread of known amps is the rareness, in terms of survivals, of original covers for Conquerors. Only one. An early amp and cab set has its cab cover. A new old stock amp cover - perhaps from early VSL days - turned up on ebay a few years ago and now joins it. But that, so far, is it. Defiant and Supreme amp covers (which are interchangeable, being the same size) survive in much greater numbers. Defiant and Supreme cab covers, certainly more numerous than those for Conquerors, are still scarce though.

Unlike covers for US solid state cabs, JMI cab covers always fit over the chrome side stands or trolleys.

9th March

The page on later JMI Conquerors now updated. Further info and pictures to come.

8th March

Pics of Supreme no. 1285 added on this page - thanks to Hans. The upper sections of the original tilt-back trolley survive. The lower section, which would have been exactly the same as the lower section of a full trolley, is gone.

The advert is later - from 1969 - but gives a good rendering of how the tilt back trolley was supposed to work. The amp was secured to the cab by chrome fixings - more on those later.

7th March

The page on Supreme cabs updated, and a page with a schema of the wiring added.

6th March

A glimpse of Keith Richards' Supreme on stage at Warsaw, 13th April, 1967, shortly before curtain up.

5th March

Pictures of a VSEL Supreme built in early 1969 now posted here. Thanks to Aart.

The preamp is stamped "JMI", but the amp has VSEL on the control panel.

The pages on Supremes have now been updated.

New updates.

May 2017.

April 2107.

Early March 2017.

Updates for January and February 2017.

Updates for 2012-2016 are on this page.

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