Low frequency amplifier VUP-30N.

Amplifying and broadcasting equipmentSince 1933, the VUP-30N low-frequency amplifier has been produced by plant No. 2 NKPT. The amplifier is an upgrade of the previous model "VUP-30". The final stage of the amplifier was removed on M-127 type radio tubes, and the rectifier on B-128 tubes, respectively, transformers and rheostats were changed in the amplifier to support these new radio tubes. The pinout of the tubes in both amplifiers is the same, so they are interchangeable with a corresponding change in output power up to 30 W on old tubes and up to 50 W on new ones.