VOX FOUNDATION BASS AMPLIFIERS

Jennings Musical Industries: 1967-1968

Foundation Bass: 50W solid state bass guitar amplifier, two channels - normal and bass. The normal channel has distortion (operated by a footswitch), and mid-range boost, operated by a switch on the control panel. The bass channel has Tone-X, a sweep tone control. Speaker cabinet was a 18" closed back unit, with a Celestion T1296 at first, later a Goodmans driver.

The analogue of the Foundation Bass in the solid state guitar amp range was the Defiant, which had the same 50W power section, but a different preamp.

In the price list of April 1967, the Foundation Bass is listed as £171 and 3 shillings - in today's money, around £2,850.

Both amp and cab were supplied with covers. Covers for the latter are exceedingly scarce these days; for the former, only slightly less so. for a fine survival.

The general characteristics of early amps are indeed much as early Defiants:

  • Serial numbers begin at 1001. Number 1165 has an original capacitor with a June 1967 date code so cannot have been ready for sale before July '67.
  • The very earliest numbers are probably in the form xxxx, as in the case of early Defiants. The standard thereafter became SB..xxxx
  • Back panels are cloth covered and have angled edges.
  • Control panels are generally deep black initially, then brown/bronze, then black again.
  • Fixings for the preamp - screws by the front corner protectors - are present on top of the wooden cases in the early amps.
  • Jack input sockets are metal and of open construction. Surrounds are white. After the first three hundred or so amps, black plastic jacks are used.
  • Logos simply state "VOX" at first in silver lettering. Later, one finds gold letters, then "Solid State".
  • The very earliest preamp sections were probably stamped: "50W. B PREAMP, SER. No. 0xxxx". Soon after the format changed to "PRE/AMP B. SER. No. 0xxxx". Later, when "Solid State" was brought into the logo, the format is:"B/S. No. 0xxxx". Power amp sections stampings are: "50W.PA SER. No. 0xxxx", then, when the preamp format changed: "P5A SER. No. 0xxxx."
  • JMI made amps always have two indicator lamps on the front panel.
  • The schematic for the preamp is OS/137, the power amp OS/134.

Below, a growing register of surviving amps. If anyone knows of any early Foundation Basses that have not yet been included, .

EARLY BLACK CONTROL PANELS

Serial number unknown - currently in Australia

No "Solid State" in the logo; control panel of the amp is black, so perhaps very early (ie. earlier than those amps with brown panels below), but unfortunately this is the only picture.

Serial number unknown - currently in France

Note the white-ringed metal jack sockets. Like the amp above, a black control panel. Potentially an early Foundation Bass. Shame the serial number plate is too small to be readable.

Serial number unknown - current whereabouts unknown

As in the case of the amp above, white-ringed metal jack sockets. Again, no "Solid State" in the logo of the amp, though it does appear on the cab's.

BROWN CONTROL PANELS

Serial number unknown - currently in the UK

Note that the logo of the cab is simply "VOX". The preamp has only one replaced capacitor. The power amp is original and untouched.

PREAMP component date codes: Yellow Lemco capacitors: "XL", "XM" and "YB" = Nov. and Dec. 1966, and Feb. 1967. Red CCL preamp caps: "L6" and "B7" = Dec. '66 and Feb. '67.

POWER AMP: RCA 2N4347 transistors are "6M" = December 1966. Red CCL filter caps: "B7" = Feb. '67. Welwyn cement resistor: "YB" = Feb. '67.

Serial number 1141 - currently in France

"Solid State" in the logo of the cab

NEW

Serial number 1165 - currently in the UK

Power amp chassis 1503, preamp 1180. The format of the preamp stamping (standard for mid run JMI bass preamps) is: PRE / AMP.B SER. No. 01180.

POWER AMP: CCL capacitors with date codes "B7" and "C7" = February and March 1967; yellow Lemco capacitor "YC" = March 1967; and wirewound resistors "YB" = Feb. '67.

PREAMP: Lemco date codes "XL" = November 1966. CCL capacitors "I6" = September 1966, and "F7" = June 1967. The amp was probably ready for despatch therefore in July/August 1967.

The main power transistors are RCA 2N4347. One can just see the "47" in the pic above. Unfortunately the surface of the metal is too pitted to make out the date code at present. For a brief overview of 2N3447s in Defiant power sections (which are identical to those of Foundation Basses), .

Serial number unknown - currently in the UK
  • 1329
  • 1329
  • 1329

Said in the ebay seller's description to be serial no. SB 2250; but this would place it in the Vox Sound Equipment period. As it is, the amp has a brown control panel, white surrounds to the metal jack plugs, top fixings for the preamp, and "VOX" in silver letters. If someone said SB 1050 or 1150, perhaps even 1250, that would be reasonable.

Updated

Serial number 1213 - currently in the USA
  • 1213
  • 1213
  • 1213
  • 1213

Excellent condition. Thanks to Kurt for the pictures. Sold on ebay in early 2018.

Serial number 1277 - currently in Germany
  • 1277
  • 1277
  • 1277
  • 1277
  • 1277
  • 1277

Sold on ebay.de recently.

A preamp surviving from an early Foundation - currently in the UK
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp
  • Foundation preamp

Preamp no. 1530. Panel brown in colour. A few new components inside, and the pilot lamps removed, but otherwise in reasonable condition electronically. The box, alas, has lost most of its fittings (apart from the "Foundation Bass" flag). Note the holes for the preamp fixing are visible in the first pic.

Date codes. Yellow Lemco capacitors "XL" and "YB" = November 1966 and Feb. 1967. Red CCL capacitors "L6" = December 1966.

Serial number unknown - currently in the UK
Serial number unknown - currently in France
  • JMI Foundation Bass
  • JMI Foundation Bass

An amp that has obviously seen some use. Indicator lamp lenses have gone (as regularly seems to have happened), but otherwise all there externally.

Serial number unknown - currently in the USA

Advertised by Guitar Center, USA, some time ago. Brown panel; condition reasonable.

"Solid State" now in the logo - input jacks black plastic.
Control panels are black again.

Serial number 1328 - currently in the UK
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328
  • 1328

Power section no. 1589, and preamp 1782. Both sections are stamped in the new format. Note that Expertly restored. Accompanied by its cab and repro chrome support.


Serial number 1329 - currently in the USA
  • 1329
  • 1329
  • 1329

A replaced mains connector, but otherwise good condition. Thanks to Mark for the pictures.

Serial number 1339 - currently in Europe
  • 1339
  • 1339
  • 1339
  • 1339
  • 1339
  • 1339

Thanks to Paul for the pictures.

Serial number 1387 - currently in France
  • 1387
  • 1387
  • 1387

Presented for sale in France last year. Complete with its stand. Condition looks good. Footswitch socket changed.

Serial number 1442 - currently in the UK
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442
  • 1442

Plenty of character - this set obviously had a good working life.

Serial number 1444 - currently in the UK
  • 1444
  • 1444
  • 1444
  • 1444
  • 1444

Sold on ebay uk in August 2015. Footswitch socket changed and a jack input renewed, but otherwise all good.

"AMPLIFIER" rather than "VOX AMPLIFIER" on the serial number plate

Serial number 1518 - currently in France
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass

.

Serial number 15(36?) - currently in the UK
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass

Sold on ebay in May 2014. Replaced indicator lamps, and lacking the grille for the back panel, but otherwise good.

Serial number unknown
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass

Amp and cab sold on ebay recently.

Serial number unknown - currently in Europe
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass
  • JMI Foundation Bass

No pics of the front. The vents on the box top, however, indicate that the amp is a Foundation Bass. "Amplifier" alone appears in the first line of the serial number plate. The footswitch socket has been replaced.