2017-04-11

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

Updates for May 2017

31st May

Some new pics of JMI Defiant no. 1484 now here. Thanks to Bernt. The serial number is the lowest to appear on a plate stating simply "Amplifier" rather than "Vox Amplifier".

30th May

The page on Vox adverts in Melody Maker, late 1970, has been updated - better images provided.

Adverts placed by Vox Sound Equipment Limited in "Beat Instrumental" in the first half of 1969 will be posted soon.

29th May (2)

A page now posted here gathering together some of the primary materials relating to the conferring of The Queen's Award to Industry on Jennings Musical Industries, 4th April 1967.

29th May

Full page "Vox Sound Limited" advert in Melody Maker, October 1970, for the Super Foundation Bass, along with the Foundation Bass, Defiant and Supreme. The texts of the blurbs come from the "Vox Sound Equipment Limited" brochure of February 1969.

28th May (3)

A page now on the preamp of Vox Supreme no. 2574, late Vox Sound Limited. Apart from a replaced volume pot, completely untouched.

28th May (2)

Dick Denney and Dave Clark with a Vox Supreme amplifier at Royston Industries head office, Hill Street, Mayfair, to celebrate Jennings Musical Industries's winning of the Queen's Award for Industry (April 1967). The event was celebrated in the Beacon Journal for July 1967.

Extract from the "London Gazette" for Friday 21st April 1967 - the page listing JMI.

28th May

Supreme 2510 (already registered)

Details of caps removed during servicing. Top, orange Sprague bias caps date code "7103" = 3rd week of 1971. Below, silver RTC with date code "7021" = 21st week of 1970.

Another late JMI Supreme - for the time being, details

Date code "8E" = May 1968.

Date code "8J" ? = September 1968.

If the date code of the transistor above really is for September 1968, then this was clearly a JMI amp that had been finished off by Vox Sound Equipment Limited, the company that formally superceded Jennings Musical Industries by August at the latest.

Mustard caps in the preamp - date codes "C7N" and "D7N" = third and last quarter of 1967.

27th May (2)

Pics of a late-ish JMI Supreme added here. Its back panel is missing, but the serial number was probably originally in the high 1100s or low 1200s. The latest component date code is November 1967.

27th May

The page on Vox Focus linesource column speakers, developed in 1970, now updated. These superceded the old LS40 and LS60 columns.

26th May (3)

The full "Vox Sound Equipment Limited" (VSEL) brochure of February 1969 from Modern Music in Dudley (and annotated with prices) now posted here, along with a transcript of its text at the foot of that page.

26th May (2)

Some new pics of Dynamic Bass serial number 1135 added on this page.

26th May

A quick shot of the relevant part of the "Focus on Amplifiers" in "Beat Instrumental" magazine for February 1970. No Vox.

Click as ever for a larger image.

Vox probably had not fully reformed yet as "Vox Sound Limited". Further info will be posted on the Vox Sound Limited page.

25th May

The Vox Sound Limited catalogue of August 1970 is now available here.

The growing sets of pages on VSL equipment will be given their own index page over the coming days.

24th May

The VSL pricelist from August 1970 now posted here.

Also to note that the issue of "Beat Instrumental" for Feb. 1970 is mighty unusual. Pages 21-36 are a "Focus on Amplifiers". We have Jennings Electronic Industries, Hiwatt, Park, Laney, WEM, Marshall, Selmer and so on and so forth, but no Vox. Vox does not exist. It looks as though things went dark for a while following the demise of Vox Sound Equipment Ltd.

23rd May

The page on Vox Sound Limited, 1970-1973, further updated. As there is a good deal more to come, it may be necessary to create a second page.

A full copy of the Vox Sound Limited catalogue and pricelist (August 1970) will be posted later this week.

22nd May (2)

A new page begun on Vox Sound Limited, 1970-1973. To be populated further over the course of this week. VSL inherited a good deal of unsold equipment from VSEL (as VSEL had done from JMI). VSL simply applied new serial number plates and, later, speaker labels. Once it had sold the existing stock of Conquerors and Dynamic Basses, however, it produced no more.

Other lines were brought in however, notably the Vox Midas - see this page - an amplifier for the Gyrotone rotary speaker cabinet. Its name was probably a dig at the flight recorder that brought down Royston Industries, and VSEL along with it.

22nd May

A notice from the "London Gazette", 26th July 1968 - the first step in the winding up of Jennings Musical Industries. On 9th August the resolution was declared and a liquidator appointed.

The two notices above - from the "London Gazette", 29 August 1968 - signalled the formal start to the winding up process, which could in some cases be fairly protracted. The important thing, however, is that JMI will have ceased in August 1968 to be a going concern - its successor was Vox Sound Equipment Limited. Note that Burndept Electronics, which assisted Vox / JMI in developing and producing the solid state line, was formally wound up alongside JMI. But Burndept, much as VSEL, continued as a new business.

21st May (2)

Above, two Belling Lee plug and socket sets. On the right, the L1722, used in Vox solid state amps. On the left, purely for interest, an unshrouded type. Spacing of live and neutral is the same in both. The L1722 gives a greater gap between the earth and other two.

21st May

The page on the Vox PA50SS and PA100SS updated further. A reasonable copy of the schematic for the SS PA50 has surfaced. Most of the other schematics that are generally available are not good.

Above, a detail of the mixer and limiter circuit boards, a little feint in parts, but moderately legible. Click for a larger, sharper image.

20th May (2)

The schematics for the Vox Midas 100 and 50 that are generally available are exceedingly poor. But one can make out the "Limiter Driver" circuits, which are presumably similar to the limiter circuit built into the Thomas Organ (US) solid state amps, an attempt to prevent output at high volumes toppling into distortion (clipping). Effectively the signal was throttled.

This reminded me of the comment by Jack Bruce in "Beat Instrumental" no. 51, July 1967:"

Evidently Jack was given a Super Beatle to use or at least try somewhere on the short US stint in late March /early April 1967.

20th May

The new page on the Vox Midas amplifier updated now with further info, and pictures of serial no. 1053

19th May

A new page on the Vox Midas begun. New pictures of a unit surviving in good condition will be posted later this weekend.

18th May

A new page on Vox Sound Equipment Ltd taking shape here.


A letter of November 1968 noting at foot the directors of Vox Sound Equipment Ltd.

17th May

The strange Vox advert in Beat Instrumental, December 1968. The drive in the latter part of the year was organs - .

16th May

The pages on PA amps and prototypes now updated. Some additions to follow.

14th May (3)

A new page on some Vox PA equipment not put into formal production.

14th May (2)

"The Senate" playing in Italy in 1968. A Conqueror at left, in the centre a slant-head AC30 (?) on top of two Foundation Bass cabs.

14th May

A new page gathering together the Beat Instrumental notices relating to the Vox solid state line, late 1967-1968, now posted here. Some new ones along with the familiar.

13th May (3)

Above, a detail from the preamp of an early Foundation Bass amp, stamped "VIB." Below, the feint remains of the same stamping on the transistor cooling mount of Supreme no. 1094. Still no indication though of what it signifies.

13th May (2)

Two great pics from Getty Images. Pentangle, with two Defiants and a Foundation Bass, at the Isle of Wight Festival, 1st August 1969; and at the Albert Hall, 17th March 1970.

13th May

From Beat Instrumental, October 1968 - Dave Roberts, demonstrator for Vox, showing Dave Davis a Supreme at the British Musical Instrument Trade Fair at the Russell Hotel, London, 21st - 25th August, 1968. On top of the amp, a copy of the Beat Instr. advert from Feb. '68.

The Vox display at the Russell Hotel, August 1968 - at this point publicly "Vox Sound Equipment Ltd". In terms of appearance, not a particularly scintillating presentation, alas (at least insofar as this shot records).

In the background, the new solid state PA amps - the SS50 and SS100 - which were noted in the Beat Instrumental report on the show (the full report lower down this page - entry for 27th April).

11th May (2)

A new page for the ads placed by Vox in Beat Instrumental magazine, late 1967 - mid 1968, is now here.

11th May

Advert from Beat Instrumental, February 1968 - still publicly Jennings Musical Industries.

No advert in the March '68 issue or anything particularly relevant to the company's name, but an interesting notice from Macari's (which had taken over the old Vox shop at 100 Charing Cross Rd.):

Note the prices of the different versions of the Gyrovox. Also, the 100W "Beatle" cabinets complete with "speaker and stand" for 85 guineas each (£89 and 1 shilling). Since Foundation Bass cabs (some of which had a 100W Goodmans driver) cost £84 in late 1967, the units in view must have been old AC100 cabs - quite a bargain. Old stock presumably being cleared out.

10th May

Above, a detail from the preamp of Dynamic Bass no. 1135. The latest observable date code appears on the red CCL capacitor - "L6" = December 1966. None of the yellow Lemco capacitors have visible codes. As noted below, the unit may have been the first Dynamic Bass preamp to be assembled, as it is stamped 01001.

Clearly if it was the first, it remained at the back of the pile for some time before being collected for this amp.

8th May

RCA 2N3055

Just to illustrate the type of box that individual RCA 2N3055 power transistors came in. Bulk packages may of course have been different in the late 1960s.

Below, a bulk pack from 1973:

6th May

The front page of the site now reshaped in prelim form. Previously rather stray pages gathered together on the first index page.

Above, Dynamic Bass preamp no. 1001 - the first made, or stamped at least - from Dynamic Bass no. 1135. Even though the preamps for the three models in the bass range were identical, Burndept indicated in the stamping the type of amp the section was to go into (30W = Dynamic Bass).

2nd May (2)

Short notice from "Beat Instrumental" magazine, September 1968 The full-page advert for Vox (page 17) was also printed in October - excerpt posted below (26th April)."

2nd May

Further pics of Conqueror no. 2029, early Vox Sound Equipment Ltd, added here. Thanks to Cem.

1st May

Dynamic Bass serial no. 1135, complete with its cover. The amp has not been repaired or modified in any way, so far as is known.

Current updates.

Updates for April 2017 are now here.

Updates for late March 2017.

Updates for early March 2017.

Updates for January and February 2017.

Updates for 2012-2016.




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