The Vako Orchestron is a keyboard instrument, which produces its sound through electronic amplification of sound pre-recorded on an optical disc. It is the professional version of the earlier consumer Optigan built and marketed by a subsidiary of Mattel in the USA in the early 1970s.
The Optigan was essentially an optical sampler. Its method of sound synthesis was optically reading graphic representations of waveforms from a series of 12 inch celluloid discs.
The business was later sold to the Miner Company in New York (organ manufacturer) who continued to manufacture the instruments and discs under the company name of Opsonar. A professional version of the machine was later marketed by Vako under the name Orchestron starting in 1975, but only about 50 were built and the company soon folded. Some later models included sequencers and synthesisers, but very few of these made it past the prototype stage.