The LS50 is RF power pentode for aircraft use at frequencies in the VHF range. The anode dissipation is 40 Watts and in Class C the output power at the highest frequencies was 40 Watts and at lower frequencies the output could rise to 85 Watts.
The GU-50 is a post war Russian copy of this German valve.
The metal top is threaded to take a Bakelite handle.
The plain top with centre thread. The top of our other LS50 has the Telefunken name moulded into it together with the Type designation and heater voltage.
The base pins are pointed for easier insertion into the base. The spigot has a guide for correct orientation as the pins are equi-spaced.
The Identification on the glass and within the anode has side flanges to give a greater area for heat radiation.
Looking at the centre of the anode. At the base can be seen that the heater wire has been coiled. The tungsten wire would have been wound on a molybdenum mandrel and then the mandrel would have been dissolved away.
The original valve-holder. The split sockets allow for secure but easy insertion of the pins. The ceramic base offers good insulation. The top of the holder would be at the front panel to allow for valve replacement in the field rather than needing the equipment to be returned for servicing. This was designed for military equipment and glass can be fragile.
Looking into the valve-holder.
The out side of the base with hollow pins for making the soldered connections.
The valve-holder with the valve inserted.
The complete assembly. Note that the sockets on the holder are held in place by brass nuts. Each socket is complex to make - not cheap mass produced tags.
All that is missing is the brown Bakelite knob.
The wide glass tube envelope is 38 mm in diameter and, excluding the base pins, is 77 mm tall.
Reference: Data-sheet. Type LS50 was first introduced in 1941. See also1941 adverts.
