Jennings Electronic Industries (JEI) J40

The solid state Jennings J40 probably first appeared in 1968, having been introduced in time for the British Musical Industries Fair in August 1968.

Beat Instrumental magazine, August 1968

An extract from Beat Instrumental magazine, August 1968, reporting on the BMI show. Mention of "transistor amplifiers from 40-100 watts" presumably encompasses the J40. At this time the company was "Jennings Electronic Developments". In 1969 it became "Jennings Electronic Industries".

The J40 preceded the Jennings AC40 (an all valve descendant of the Vox AC30) by around eighteen months. On this last, .

The Jennings J40 listed in Beat Instrumental magazine, February 1970

Above, a section on JEI in the "Focus on Amplifiers" published by "Beat Instrumental" magazine, February 1970. The J40 cost £130.

  • The Jennings J40 in the JEI pricelist of 1972

A detail from the JEI pricelist of December 1972. The J40 now costs £140.00.

In common with the Jennings J100 (and the Vox solid state line), the J40 had a three position mid-range boost switch, position "0" being off, the other three (1-3) switching in an inductor and capacitor network to provide different resonances.

No schematic for the amp has yet come to light. Speakers are Celestion alnicos, apparently T1096s, wired in parallel for a total impedance of 15ohms. See the original sticker in the amp a little way down this page.

Some surviving amps

  • An early Jennings J40
  • An early Jennings J40
  • An early Jennings J40

Possibly an early amp. The power section sits on the bottom of the box. The back panel has a central cut-out similar to the ones that Denney devised for the Beatles' early AC50s cabs. Denney of course was Tom Jennings's right-hand man at JEI.

  • JEI J40, general view
  • JEI J40, side
  • JEI J40, general view
  • JEI J40, inputs
  • JEI J40, tone controls
  • JEI J40, tone controls
  • JEI J40, speakers
  • JEI J40, serial number plate

Excellent cosmetic condition. Currently in the UK. The Fane speakers are probably replacements for the Celestion originals.

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Currently in the USA. The original Celestion T1096s survive along with the note about speaker wiring.

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  • jennings J40
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The Arctic Monkeys in the studio with a solid state Jennings J40.

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