The Roland CompuRhythm CR-78 was introduced in 1978 by the Japanese Roland Corporation. Its front panel doesn’t feature the 16 patterns keys that will become a standard later, thus actually it is more described as a rhythm machine rather than as a drum machine (maybe also because of its 34 in-build preset rhythms, from rock and disco to swing and tango). Although primitive by today’s standards, the CR-78 represented an important advance in drum machine technology at the time, in particular by allowing users to program and store their own drum patterns.
The LM-1 Drum Computer, manufactured by Linn Electronics Inc., was the first drum machine to use digital samples of acoustic drums and also one of the first programmable drum machines. It was conceived and designed by Roger Linn, a semi-professionnal guitarist in California, USA in 1978.
Successor of the TR-808, the Roland TR-909 Rhythm Composer is a partially analog, partially sample-based, drum machine introduced by Roland Corporation in 1984, and produced until 1985. Around 10,000 units were made during this period.
Launched in 1984, the Roland TR-707 Rhythm Composer is a programmable digital sample-based drum machine. It was the first 100% digital drum machine built by the Roland Corporation. Underrated compared to the TR-808 and TR-909, it has a Matrix display to show the patterns map and features some drum samples that sound almost identical to the TR-909. Also a memory cartridge can be plugged in a front slot for instantaneous loading and saving of patterns and expanding memory by three times.
The Roland TR-727 Rhythm Composer. Visually identical, aside of a different blue color layout, it is a TR-707 version (from the same period) with a Latin inspired drum samples set.
Sources: Wikipedia, Vintage Synth Explorer, Synthmuseum, Attack Magazine
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