The CV450 is a television line output pentode based on the Mullard EL38.
The KB/DA identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the DA identifies the maker as Mullard Radio Valve Co., Blackburn.
The ceramic insulators are present because of the high transient voltages involved in line output stages. Above the lower mica the white of the coated cathode tube has the copper of the control grid supports either side. The screen grid wires cab=n be seen to have an open pitch compared to the control grid. This lowers the screen grid current.
Looking along the grid axis. The fin at the top is for cooling the control grid. Too hot and the wires start to emit electrons.
A closer view of the base showing all three wire grids and their relative pitch.
The main top mica showing the shaped cathode tube. The anode connection to the top cap passes through the very top mica.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 123 mm tall.
Reference: Data-sheet. Type CV450 was first introduced in 1946. See also1946 adverts.
