The Vako Orchestron is a keyboard instrument made in the 1970s, that produces its sound through electronic amplification of sounds pre-recorded on an optical disc. It is the professional version of the Mattel Optigan, an earlier and lower-priced model intended for amateur musicians. History Vako Synthesizers Incorporated, founded by electronic instrument pioneer and former Moog technician and salesperson David Van Koevering, started to build improved versions of the Optigan under the name Orchestron in 1975. Intended for professional use as an alternative to the Mellotron (hence the name Orchestron), it featured improved recorded sounds over the Optigan. The Optigan was an organ that played its sounds from light-scanned graphic waveforms encoded on film discs. The sounds with the highest fidelity were on the outer rings of these discs, and these outer rings were used for the Orchestron sounds to improve the sound. Although the Model A Orchestron is identical to the Optigan, the models B, C, and D follow the designs of the Chilton Talentmaker. The Talentmaker was taken out of the market after Optigan's manufacturer – Optigan Corporation, a subsidiary of toy company Mattel – threatened to sue Chilton because of patent infringements. Some Orchestron models included sequencers and synthesizers. These were the larger Model X and Phase 4 units, though very few of these made it past the prototype stage. While the same fidelity limitations of the Optigan applied to the Orchestron, these instruments were built to be more reliable and were used successfully in commercial recordings. The band Kraftwerk made heavy use of the Orchestron on their albums Radio-Activity (1975), Trans Europe Express (1977) and The Man-Machine (1978). It is a common misconception that the band Yes used the Orchestron on their Relayer (1974) album. In fact, keyboardist Patrick Moraz did not acquire his until 1975 or 1976. He used the Orchestron on Yes' 1976 tour. The Orchestron was not a commercial success, though. An estimated total of 70-100 units were built before production ceased after a couple of years. Its rarity and popularity amongst low fidelity enthusiasts makes the Orchestron highly sought after. Technical description The Orchestron uses basically the same principle as the Optigan: each note of the keyboard is recorded in an infinite track on a pre-recorded, interchangeable optical disc. A beam of light is sent through the disc; variations in the light intensity are detected and amplified. Originally, there were only eight sounds