- Anne Beetem Acker
Monophonic vacuum-tube-based keyboard synthesizer introduced by the Hammond Instrument Co. of Chicago in 1940 and manufactured into the 1960s. The first commercially available piano attachment, it was intended to accompany a piano with sustained sounds, but was also used separately especially by rock and roll, country and western, and polka bands. The model J (1940) was followed by the model K (1946) and model L (1948). A patent covering the ‘tone cabinet’ containing the electronics and loudspeaker was issued to Laurens Hammond in 1940; patents for the keyboard design and electronics followed in 1941. George H. Stephens and John M. Hanert were part of Hammond’s design team.
When used with a piano the three-octave keyboard is aligned in front of and slightly lower than the piano keys. The connected tone cabinet can be placed on the floor, or be mounted beneath grand pianos. A ‘military’ version includes the loudspeaker and keyboard in the same cabinet. Thumb controls select the octave in which the notes will sound, the tone quality (deep, full, first voice, second voice, brilliant), a fast or slow attack, and turn off the default vibrato. An optional ‘Mute Control’ stresses the odd harmonics to sound more like woodwinds. Volume is controlled by a lever usually operated by the knee. Two tuning adjustment knobs are used to match the pitch of the host piano or accompanying instruments....