The Hammond Solovox (1940)

Hammon Solovox
The Model J Hammond Solovox
(Photograph courtesy of Eric Barbour, Svetlana Electron Devices)

material sourced from http://www.obsolete.com/

The Solovox was designed by Alan Young of the Hammond Organ Co and manufactured in the United States between 1940 and 1948.The Hammond Solovox was a monophonic keyboard attachment instrument intended to accompany the piano with organ type lead voices.

The 3 octave short keyed keyboard was stored on a sliding mounting under the piano keyboard with a knee operated volume control. The Solovox was connected to the electronic sound generation box and speaker housing by three thick cables. The sound was derived from a single LC oscillator which had a frequency range of one octave. The signal from the oscillator was then passed through a series of 5 frequency dividers to create a further two octaves. The Solovox (J+K models) used two vibrating metal reeds modulate the oscillator frequency to create a vibrato effect, in later models this was replaced by a second oscillator acting as a vibrato oscillator.

On the front of the instrument below the keyboard there were a series of large thumb operated buttons for oscillator range (switch-able +/- 3 octaves: 'soprano', 'contralto','tenor' , 'bass'), vibrato, attack time, 'deep tone', 'full tone', '1st voice', 2nd voice', 'brilliant' and a switch for selecting woodwind, string sound or mute. The Solovox was able to create a range of string, woodwind and organ type sounds and was widely used in light music of its time.

Read this interesting article:

http://antiqueradio.org/hammond.htm