An ahead-of-its-time drum machine produced by the organ manufacturer Wurlitzer, in 1958. The Sideman was intended to be used as an accessory to Wurlitzer organs; it was on wheels and was intended to be portable. It included a built-in amplifier and loudspeaker. It is usually considered to be the first drum machine with electronic sound generation (i.e., not based on tape loops).
Being that transistors were not yet widely available in 1958, the Sideman used vacuum tubes (valves) for both its signal generation and amplification. The unit had circuits for ten different percussion sounds, including kick, toms, cymbals, and various kinds of blocks and claves (no snare). The blocks and cymbals had five possible tonal variations, selected by rotary switches.
As was the case for all pre-1970s drum machines, the Sideman had fixed (not programmable) patterns. Nonetheless, the unit was fairly versatile, having 11 patterns plus a metronome setting. And as was the case for most units of this era, the patterns were named after popular ballrom dances, including "rhumba", "waltz", "bolero", and "tango". The "foxtrot" pattern had 2/4 and 4/4 variations available, selected by a switch. A lamp on the panel flashed on the quarter note, serving as a visual indicator of tempo. The machine sequenced the patterns with an electromechanical device called a commutator, basically a large motor-driven rotary switch. Tempo was controlled by varying the motor speed. Some sub-switches, driven by an arrangement of belts and pulleys, handled certain aspects of patterns and variations.
The control panel included buttons for manually triggering each of the percussion sounds, along with the pattern select and tempo controls. A start/stop switch electrically stopped the motor; the user had to watch the tempo indicator and listen to the pattern to determine where to stop so that it would restart on the 1 beat when run was selected again. A remote control box was available for mounting on an organ console, and it allowed the perfomer to remotely start and stop, select patterns, and control the output volume.
It is not known how many Sidemans were built. Musicians' unions in New York and London were politically powerful at the time, and they put pressure on Wurlitzer to discontinue the unit. (This despite the fact that most of the sounds were not very realistic, and the pattern capabilities were very limited by today's standards.) It was apparently off the market by 1962.