Hammond BC Electronic Tonewheel Organ

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The Hammond BC organ was produced from 1936 to 1942 and followed the Hammond A (1935-1938), the earliest model of a tonewheel organ from Hammond. It is almost identical to the model A-B (1936), but also has chorus and a second tone generator. The smem model is housed in a portable casing.

The Hammond BC is equipped with 2 manuals of 61 keys, a bass pedal with 25 keys, 9 presets per manual, 4 sets of 9-course drawbars, two generators and a tremulant control. It is a tonewheel model with generators consisting of rotating steel tone wheels and electromagnetic pickups. The shape of the teeth results in a sine-like oscillation, which is smoothed by a filter circuit to an almost ideal sine wave. The alternating voltages generated are channelled through the manuals, the drawbars and the vibrato circuit. An amplifier stage amplifies the sound signal to such an extent that a loudspeaker can be driven. (Source: Wikipedia)