Theremin virtuoso Konstanin Kovalsky (1890-1976) performs with Vyacheslav Mescherin’s Orchestra of Electronic Instruments, USSR, 1960. From Discogs:
The Ensemble of Electro-Musical Instruments directed by Vyacheslav Mescherin was founded within the music department of the State Radio of the Soviet Union in 1957. For more than thirty years, from the Fifties up to the Eighties the music of Ensemble Mescherina could be heard on radio and TV, in radio plays and cartoon movies almost every day. The ensemble managed to compose more then 700 pieces of music until 1990. Some of Mescherins compositions are public domain by now and can be hummed by everyone in Russia. One example is the track ‘On the chicken farm’, which was used in the very popular cartoon series ‘Rabbit and Wolf’. In 1959 the Soviet government asked Mescherin for an electronic sound recording of ‘The Internationale’, to be sent to outer space on board of the first sputnik. Mescherin also designed and built many electronic instruments himself. Balalaikas, accordions and guitars, which he amplified, now sounded as if played on another planet. Mescherin and his ensemble were more or less the only experimental musicians in the field of electronic music in the USSR up to the Sixties.
(via r/VintageObscura)