Jennings Organs in Alan Douglas's "The Electronic Musical Instrument Manual"

An advert - not encountered elsewhere so far - for the J51 "Streamline" organ in the second edition of Alan Douglas's "The Electronic Musical Instrument Manual" (London, 1954). The first edition had come out in 1949 and needed revising.

Although nothing is said explicitly about Jennings in the main text of the 1954 and 1957 editions - probably because Douglas had amassed enough illustrative material from other manufacturers to make his points - various observations were introduced in the fourth revision of the "Manual" in 1962 (see further below).

1954 edition, advert at the end of the book.

1957 and 1962

Below, two ads for the Jennings D2 "Entertainment" organ, 1957 and 1962, third and fourth editions of Alan Douglas's "Manual".

From early 1961 Jennings offered prospective customers the chance to hear any model in its range "at home", or in the building in view - church, chapel, assembly hall, and so on. For the larger units, at least four Jennings engineers will have been required to do the lifting and carrying. The Temple Bar telephone number was for the shop at 100 Charing Cross Road.

1957 edition.

1962 edition.

Detail from the page above.

The transistorised "effects" assembly was first signalled (new) in August 1959. Quite what the source of the circuitry was is unknown, possibly "in-house" design, though more probably borrowings from some American-made organ - a Thomas perhaps. The arrangement to distribute Thomas organs on an "exclusive" basis in the UK did not come until later though.

Below, the frontispiece of the Fourth Edition (1962).

Frontispiece, 1962 edition.

Remarks introduced in 1962

Below, the oscillator circuit (for the dividing chains) replicated from an unknown model (or models) of Jennings organ. There are points of contact with the revised circuits of the Model A, B and E organs, members of the "V-series" introduced in mid 1956, but the match is by no means exact. It may be that the circuit reproduced by Douglas is of the D1 and D2 "Entertainment" organs. Since the surviving circuit diagrams give only cursory details, it is probably best to leave the question open for the time being though.

1962 edition, pages 74 to 75.

Last but not least, there is on pp. 154-158 a fairly lengthy analysis of the Univox, with inset illustrations and a circuit diagram. It is not clear why no mention had been included earlier. The Solovox and Clavioline were covered in the 1954 edition. In 1962 the Univox was over ten years old. Perhaps Douglas had been misled by its resemblance in terms of general outward appearance to the other two units. His section on the Univox begins with the substance of the patent awarded to Les Hills and Jennings for the "Electrical Oscillation Generator", moving on, albeit briefly to various aspects of the tone-forming circuits.

More to come on Douglas's discussion on a set of new pages (forthcoming) that will be linked in here.

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