E K L - 34
The 5-tube R-set of direct amplification "EKL-34" was produced by Leningrad Kozitsky Works (earlier spelled "Kazitsky") from 1934 and was an improved version of the "EKL-4" set. The difference was a better technology and characteristics. In the author's collection the set has the serial number 3903.
BASIC TECHNICAL DATA.
Set of tubes: SO-124, SO-118, SO-118, UO-104, VO-166
MW 225-720 m; LW 680-2000 m
Sensitivity - 40-300 mcV/m
Power output 0.8 W
Power consumption 65 W
Dimensions 520õ420õ260 mm
The set was put into a massive wooden cabinet made of plankets cogged together. The upper part of the case is removable. To insure access to the tubes the lid has two detachable hatches from behind and on the right side. They are draped with grill cloth.The base of the cabinet which has a function of the chassis is covered by a veneer lid from below.
The AC-switch of lever-type is placed on the left side of the base. The vertical moving dial of 20x25 mm has a pointing in fixed units, a light, a wire pointer. Beside the dial there is the control handle of the 3-section tuning capacitor . The two knobs on the base control volume and positive feedback. Wire potentiometers wound on wooden rings are used for control. In the center a small lever with horizontal move is the band selector. The two levers to the left serve for fine tuning of RF coils for maximum sensitivity during listening. The set has a couple of adapter terminals to connect with a gramophone. The switching of the AC voltage of 110-127-220 V is made by resetting of the jumpers on the net transformer. The loudspeaker has a 3-section field coil. The outer side of the glued paper cone is made of natural leather.
The R-set is built according to the structure of direct amplification 1-V-2 with controlled positive feedback using tubes of the indirect 4-volts heating. The RF amplifier on a tetrode SO-124 has the cap coupling with the aereal. A SO-118 tube works as the detector. The first AF step is built on a similar tube. The output audio step is working on a direct heating triode UO-104. The scheme is sourced on a rectifier VO-116. All the resistors are carbonic ("Kaminsky" type). The filter caps are paper-made (Leningrad "Krasnaya Zarya" Works), the rest are of open construction made of mica.