The Hammond Novachord (770258), introduced in 1939, generated sound using vacuum tube oscillators and frequency dividers. By adjusting a series of knobs, a musician could produce a range of novel and conventional instrumental sounds. It was often heard on the radio and featured in several film scores, but it was complicated to play and service. Hammond ceased production in 1942 after making just 1096 instruments.

1940s Hammond Novachord and a portion of its vacuum tube electronics (CSTM)