The KTW63 is a beam or kink-less tetrode for HF and IF amplification in broadcast receivers and replaced the W63. The valve is variable mu designed to have the stage gain controlled by a voltage derived from the final rectified signal.
Note: The 6K7 family has pin 5 connected to the suppressor grid whereas the KTW63 has an internal connection to g3 and pin 5 has no connection. These valves are sensibly equivalent but not identical.
The Marconi paper label, like the Osram and GEC brands they are made by M-OV.
The top screen showing the top of the control grid copper supports and the connection to the top cap. The cathode is a round tube and above the inner coating can be seen some of the wire grids.
The classic envelope is 38 mm in diameter and, excluding the IO base pins the valve is 104 mm tall.
References: Data-sheet & 1040. Type KTW63 was first introduced in 1938. See also1938 adverts.
