The instrument
Hammond Organ Company introduced the chord organ in 1950 with the S series. Its "easy to play" style initiated a new market segment leading to today's home keyboard market. The chord organ was invented primarily by John M. Hanert, who was Hammond's primary musical engineer at the time. He had previously developed the Novachord and Solovox, two instruments which used vacuum-tube circuitry rather than tone or phonic wheels to generate the tones as in a Hammond Organ. Chord organ is a kind of home organ that has a single short keyboard and a set of chord buttons, enabling the musician to play a melody with one hand and accompanying chords with the other, like the accordion with a set of chord buttons. There were five different versions of the basic Chord Organ, which was called the S-series. The original model "S" used octal tubes and one 12" speaker while the S-1 used miniature tubes and one 12" speaker. (source: Wikipedia)
Details
The S-6 chord organ can be played via following interfaces: 37 full-sized keys (F to F; 3 octaves + semitone) for controlling organ and solo voices; 96 chord buttons, with 12 roots arranged in perfect fifths and 8 chord types; two foot pedals for playing the root and fifth of the chord selected; monophonic solo voice with bass, tenor, soprano, 5 timbres {deep tone, full tone, first voice, second voice, brilliant}, woodwinds tone, percussion, fast attack/fast decay (with percussion); semi-polyphonic organ voice, with two timbres {strings, flutes}; vibrato with cancelling tabs for organ and chords, solo wide, and solo small; volume soft; pedal, organ and solo volume knobs; knee lever acting as both an on/off switch and volume control; two 10" alnico speakers. (source: crasno.ca)