On this page - currently building - some notes on the harmonic drawbar designed for Jennings organs by Derek Underdown and Geoff Harris in 1957 and first incorporated in the "entertainment" consoles of 1958, notably the Model B, D1 and D2 - see the advert at the head of this page.

The patent was applied for on 31st October and granted on 27th April 1960. The design (from point of view of appearance) was registered in late 1957.

The drawbar was in effect a complex sliding switch, allowing different voicings to be activated as the bar was pushed or pulled from contact point to contact point. Gone were the days of one drawbar per voicing.

Photograph from late 1957.

Brochure from c. 1958. Thanks to Martin Kelly for the image.

In 1962, the drawbar assembly was developed further for the new Vox Continental organ, shown for the first time at the Russell Hotel Trade Fair (in August). The assembly was the basis of Jennings's assertion of "world patents" for the organ.

The drawbar assembly in a Vox Continental from mid 1963. A fuller picture to be supplied shortly.

Pages on Jennings organs, 1954-1957, can be found here. Other years will follow soon. A sequence of pages on guitar amplifiers, beginning with 1958, starts here.

Photographs from late 1957.

The text record, 1957. Protection for the design was renewed into 1967.

Header.

Figures.

Text, page 1.

Text, page 2.

Back to the main index page.

Documents relating to Jennings (Vox) guitar amplifiers, 1957