Vacuum tube radio receiver `` VEF M-697 ''.
Tube radios.DomesticSince 1949, the VEF M-697 network lamp radio receiver has been produced by the VEF State Electrotechnical Plant. The VEF M-697 radio receiver is based on the VEF M-557 receiver. In the new receiver, the circuit for regulating the IF bandwidth was eliminated, which was replaced with a step-type HF tone switch, which did not have the best effect on the reception quality. The owners of the receiver had complaints about the instability of the local oscillator in the HF range. After 8 months of release, the model was discontinued and replaced by a new, more advanced Baltika model. The receiver is assembled on 6 lamps. The frequency converter is made on a 6A7 lamp, an IFU on a 6K7 lamp, an AGC detector and a preamplifier for low frequencies on 6G7, an end amplifier for 6P6S, an optical tuning indicator for 6E5S, a rectifier unit for 5Ts4S. The speaker uses a dynamic high-sensitivity loudspeaker with a combined magnetic system with a permanent magnet and a magnetizing coil, which is also used as a filter choke. Output power 2 W. Ranges: DV 150 ... 410 kHz, SV 520 ... 1500 kHz, KV 4.28 ... 12.1 MHz. The IF is 469 kHz. Sensitivity from the antenna to LW and SV 200 µV, HF 300 µV, from the pickup jacks 0.25 V. Selectivity on the adjacent channel 26 dB on LW, MW, 12 dB on HF bands. Attenuation of the signal along the mirror channel by more than 30 dB in the ranges of LW, MW and 12 dB at HF. The range of reproducible sound frequencies is 100 ... 4000 Hz. Power consumption 67 watts. Receiver dimensions 560х360х250 mm, weight 13 kg. The plant also produced complete sets for self-assembly of the VEF M-697 receiver.
