“Yalkyn”, Tatar for “flame”, was a three-channel automatic light-music installation with a cube-shaped screen. Two smaller cubic stencils rotated inside it. They were made from transparent glass or sheet duralumin, and some openings contained lenses. Three BK100-220 V lamps sat inside the smallest cube.
Electronic and mechanical components were housed in the base beneath the lamps. A single electric motor drove both the cooling fan and the rotating stencils.
“Yalkyn-1” had an outer screen of milky Plexiglas. “Yalkyn-2” used transparent Plexiglas, exposing the structure. In one version of “Yalkyn-2”, mirrors covered the two rear walls. They multiplied the rotating stencil patterns like a kaleidoscope and projected light onto the surrounding walls, floor and ceiling.
To avoid a fixed link between pitch register and colour, signals from the band-pass filters could be routed manually to any of the three power channels. A background channel operated when there was no musical signal.
Different versions used different colour systems. Some fitted cylindrical filters directly over individual lamps. Others used a single cylinder with bands arranged in a continuous colour cycle inside the moving stencil. The first method illuminated separate areas of the screen; the second produced a smooth, continuous change of colour.
“Yalkyn” appeared several times at the Exhibition of Achievements of the National Economy and at Soviet exhibitions abroad. One example was presented to the 17th Congress of the Komsomol and another to the Soviet cosmonaut corps in 1980.
After construction details appeared in To Help the Radio Amateur (no. 52, 1976, pp. 9–21), letters sent to Prometheus suggested that hundreds of radio amateurs across the USSR had built their own versions.
