This exhibit has the paper Air Ministry label on side giving the valve the type designation of KTW62. The valve was M-OV supplied during WWII for RAF use. It is a variable-mu IF kinkless tetrode of the 6K7 class but with slightly more gain. Thousands were supplied with the KTW62 used in the CR100.
The grey plastic sleeve between the base cap and envelope looks to have been added at manufacture to improve the life of the base to glass seal. As many of these valves went to the Royal Navy and Army vibration was going to be a possibility during service.
There are no marks on the reverse.
Top view: screening covers all but the tops of the electrodes. The copper control grid support is connected to the top cap.
A view of the CR100.
The classic envelope is 38 mm in diameter and, excluding the IO base pins, is 101 mm tall.
References: Data-sheet, 1040 & 1043. Type KTW62 was first introduced in 1939. See also1939 adverts.
