Low frequency amplifier VUP-30.
Amplifying and broadcasting equipmentSince 1930, the VUP-30 low-frequency amplifier has been produced by plant No. 2 NKPT. The amplifier is designed to operate on small radio broadcasting nodes to serve up to 300 subscriber radio outlets. To drive the amplifier up to 30 W, a preamplifier "UP-3" is used, and since 1931 "UP-3-N" is used.