Synth geeks might want to have a look at the Vintage Synth Explorer Timeline. It'snot exhaustive, but it's high on trivia and well-written. The oldest entry is for the Chamberlin Rhythmate, a drum machine made in 1949:
The Chamberlin Rhythmate has the distinction of being the first drum machine ever produced. Only around ten were made by Harry Chamberlin from his Upland, California garage back in 1949. Some have said that the Wurlitzer Sideman was the first drum machine, but Chamberlin's invention preceded it by ten years.
The Rhythmate uses a 1" magnetic tape loop which is read by a tape head that can be moved up or down to play back 14 separate drum patterns. The tempo is adjusted by moving a spindle up or down which affects the speed of the tape moving across the head. The Rhythmate has a built-in amplifier and 12" speaker.
In 1951, Harry Chamberlin used his idea of magnetic tape playback (samples) to create the Chamberlin Model 200 keyboard. The Model 300/350, 400, 500 and 600/660 models followed.
In the mid 1960's, Harry's concept was used by Mellotronics to create their now famous line of Mellotron keyboards. Mellotronics did not ask Mr. Chamberlin for permission to use his idea and he was not at all happy about it. But they agreed to pay Harry $30,000 in compensation, which was quite a bit of money in 1966.
» vintagesynth.com
(thanks: Colin Robinson)