Wire tape recorder '' PM-39 ''.
Tape recorders and radio tape recorders.Since 1939, the wire tape recorder "PM-39" has been produced by the Leningrad Plant named after V.I. Kazitsky. Rather, he did not produce but altered the devices of the firm "C. Lorenz" purchased in Germany on domestic radio tubes and put plates with Russian inscriptions. At a time when the Germans already in 1935 demonstrated the tape recorder invented by them with the recording of phonograms on magnetic tape, the USSR continued to develop sound recording equipment on other media. A lot was developed, but it did not fit industrial production. Therefore, for the needs of various departments (mainly the military), a batch of wire tape recorders was purchased in Germany and transferred to the Kazitsky plant. After the alteration, the device received the name "PMrkt-39", later simply "PM-39" (Wire tape recorder of 1939). The tape recorder was an exhibit at the Polytechnic Museum in Moscow. It has no name and is dated 1941. In the tape recorder, a thin steel wire was used on a reel containing it about 4 ... 4.5 kilometers. The speed of drawing the wire through special, separate heads is variable and was regulated from 10 to 60 cm / sec. The operating frequency range of sound is 300 ... 7000 Hz at maximum speed. Recording or sounding time of one reel up to 24 hours.
