Jennings Electronic Industries AC40

Introduced in time for the Associated Musical Instrument Industries fair in August 1970, the AC40 was the first valve amp in the "Jennings Electronic Industries" range. Everything up to that point had been solid state. To some extent, the appearance of the amp represents a capitulation on the part of Tom Jennings, who had hitched his wagon firmly to transistors, to the demands of the market.

jennings ac40

Notice from "Beat Instrumental" magazine, October 1970. Price of the AC40: £85.

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Preview of the Associated Musical Instrument Industries fair published in "Beat Instrumental" magazine, August 1971. Price of the AC40 is now £150. Draw-bar controls are still in place.

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A detail from the JEI pricelist of December 1972. The AC40 costs £150.00 (its price also in August '71.

Whether the AC40, which is cathode biased like the AC30, actually made 40 watts is doubtful. If it did, it must have run extremely hot. As the articles in BI mention, the first amps - from August 1970 to August 1971 (and later) - had novel organ-like draw-bars for the controls.

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Above, an early JEI AC40 photographed with an AC30. Controls for the Vib-Trem were standard.

To date no schematic of the AC40 has come to light - but its circuit is not that far removed from that of an AC30.

Speakers are either Celestion alnico T1096s, 15ohms, wired in parallel for a total impedance of 8ohms, or ceramic Celestion T1217s, wired in the same way.

Some surviving amps

Serial number 1235

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Note that the speakers are alnico Celestion T1096s - the 15ohm counterpart of the T1088. The frames of T1096s, as here, are normally sandy in colour, and the bells silver.

Serial number 1254

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A gorgeous Jennings AC40 and matching 2x12" extension cab. Condition is immaculate. Grey-back Celestion G12H drivers in the AC40, and greenbacks in the extension cab. The date codes of the latter are LE28 = 28th November 1972. Mustard caps in the amp have 1970 codes. Thanks to Andreas for the pictures.

Serial number 1278

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Date code of the remaining original Celestion T1096 is DF6 = 6th April 1973. The other speaker is a replacement.

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Illustrated on this site - click here

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An unused panel marked in the far right hand corner "AC30", but probably for the amp generally known as the AC40, sold on ebay in 2012.

Click here for the Jennings J40, the solid state precursor of the AC40.