VOX DYNAMIC BASS AMPLIFIERS

Jennings Musical Industries (JMI) 1967-1968

The caption reads: "A 50 watt peak power bass amplifier with a bass tone as rich and deept as a newly tapped oil well, and yet with fantastic tonal variation (exclusive TONE-X gives you this). The separate frequency-tuned speaker cabinet houses a special 15 in. loudspeaker. Four inputs through two channels. Supplied with roll-away stand. Dimensions:

Amp. Section - 23 3/4 in. x 9 1/2 i.n x 9 1/2 in.

Speaker Section - 24 in. x 25 in. x 15 in.

In actual fact the output of the Dynamic Bass by conventional measurement (rather than peak power) is more like 30W. The amp had two channels - normal and bass, the normal channel with distortion (operated by a footswitch) and mid-range boost (MRB); and the bass channel Tone-X, a sweep tone control. Speaker cabinets were normally provided at first with a Celestion T1109 driver, later a Goodmans unit.

The analogue of the Dynamic Bass in the solid state guitar amp range was the Conqueror, which had the same 30W power section, but a different preamp.

The Dynamic Bass, however, was not produced in such great numbers as the Conqueror. It is worth noting too that the Dynamic Bass and Conqueror amp sections were slightly smaller than the other amps in the range (Foundation and Super Foundation Bass; Defiant and Supreme).

The price list of April 1967. The Dynamic Bass cost £149 and 2 shillings, in today's money, around £2,500. To give some context, the list sets the AC30 almost on a par at £143.

In terms of general characteristics (and changes):

  • Serial numbers begin at 1001.
  • 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.
  • Logos simply state "VOX" at first in silver lettering. Later, one finds gold letters, then "Solid State" (by serial no. 1198).
  • Jack input sockets are metal and of open construction. Surrounds are white. After the first two hundred or so amps, black plastic jacks are used.
  • Preamp sections are stamped PRE/AMP B. SER. No. xxxx. Power amp sections: 30W.PA SER. No. xxxx. A diffferent format was adopted towards the end of the JMI period. Power amps came to have: P5A SER. No. xxxx.
  • JMI made amps always have two indicator lamps on the front panel.
  • The schematic for the preamp is OS/137, the power amp OS/133.

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

Serial number 1029 - currently in the UK

Thanks to Paul Johnson for the info.

Serial number 1048 - currently in the UK

Thanks to Paul Johnson for the info.

Serial number 1063 - currently in the UK

Updated

Supplied by Cooke's "Everything Musical" of Peterborough. The cloth has browned like that of certain early Foundation Bass sets. Good to see the Belling Lee mains input socket still in place.

Serial number 1087 - currently in Germany
Serial number 1121 - currently in Belgium

Great condition. Thanks to Jullian for the pictures.

NEW

Serial number 1135 - currently in the UK

In great condition and with its original cover. Only a few new caps in the preamp.

Serial number unknown - currently in the UK

Sold on ebay.uk in the 2000s. Probably a very early one. Note the blackness of the control panel.

Serial number unknown - currently in the UK

A nice amp - as above, probably an early one. Black control panel.

Serial number unknown - currently in France

A complete set. Apparently a black control panel.

Serial number unknown - currently in Europe - twin locations given: Slovenia and Czech Republic

Brown control panel. Pictures originally posted here.

Same amp as above (note the damage to the serial number plate)

Pictures posted here.

Serial number unknown

A good looking amp. Brown control panel, and cloth faded to brown too.

"Solid State" now in the logo. Black plastic input sockets.

At this point too the preamp fixings on top of the box disappear

Serial number 1177 - currently in the USA
Serial number 1187 - currently in the UK

Replaced grille cloth front and back, otherwise in good condition. Pictures of the preamp show that one of the red filter caps has the date code "G7" - August 1967 - giving a useful point of reference.

Serial number 1198 - currently in the UK

Thanks to Steve for the pictures.

Serial number 1241 - currently in the USA

Still "Vox Amplifier" on the serial number plate. Formerly owned by Reisz Promotions in Germany. The entire collection at Reisz Promotions (which was large) was bought by Music Center and shipped to the USA in the late 2000s.

Serial number unknown - currently in the UK?
Serial number unknown - currently in Germany?

A nice full rig sold on ebay.de some time ago.

Serial number unknown - currently in Germany?

Another nice rig, complete with chrome amp support. The number is frustrating difficult to make out on the plate - the second digit is "0" the last "4", but the others are indistinct. It could be no. 1094 or even perhaps 2004.

"AMPLIFIER" alone on the serial number plate

Serial number unknown - currently in Europe

Advertised on vintageandrare a little while ago. Control knobs replaced, but otherwise a nice example. Probably one of the last JMI units made.


On to the next page of Dynamic Basses.