Network tube radio receiver `` ECHS '' (ECHS-1).

Tube radios.DomesticThe "ECHS" (ECHS-1) network lamp radio receiver from the middle of 1930 until the year was produced in a small series by the Moscow Electrotechnical Plant "Moselectrik". The ECHS receiver was developed at the end of 1929 by the Leningrad Central Radio Laboratory of the VEO and in December 1929 it was transferred for serial production to the Moselectrik plant. Comprehensive testing of the receiver by the plant showed that it works rather mediocre, at least not better than the serial acceptance of the "Warhead". The radio was rejected and recycled. As a result of the modernization, a receiver with the name "ECHS-1" was prepared for serial production, however later in everyday life and in technical documentation it was called "ECHS". Receiver "ECHS" (ECHS-1) (shielded, four-lamp, network) is the first radio receiver with full power supply from the AC mains assembled according to the 1-V-2 direct amplification scheme with inductive-capacitive feedback. A SO-95 shielded, heated lamp with a gain of 200 was operated in the high-frequency amplifier. Detection (grid) was carried out with a PO-74 lamp (receiving oxide with heating). The low frequency amplifier had 2 stages of amplification on transformers. The TO-76 lamp (thoriated, oxide) operated in the first stage. The thick filament of the lamp allowed for AC power. At the output of the receiver, there was a UK-30 type lamp (amplifying carbonated), which was an improved sample of the UT-15 type lamp. Its thorium filament is covered with a layer of coal, which prevented thorium from escaping from the filament during overheating and made it possible to power the lamp with alternating current. The receiver was powered by a rectifier operating on two UT-1 lamps (the K2-T kenotrons were too low-power). The "ECHS" receiver in the spring of 1931 was replaced by a new, improved "ECHS-2" receiver, in which new lamps were used.