The Rudolph Wurlitzer Company released an early commercially produced drum machine called the Sideman in 1959. It was an “electro-mechanical” drum machine that offered a choice of 12 electronically generated predefined rhythm patterns with variable tempos. Look for the original advertisement below the video.

The sound source was a series of vacuum tubes which created 10 preset electronic drum sounds. The drum sounds were ‘sequenced’ by a rotating disc with metal contacts across its face, spaced in a certain pattern to generate parts of a particular rhythm. Combinations of these different sets of rhythms and drum sounds created popular rhythmic patterns of the day, e.g. waltzes, fox trots etc.