The 6101, also marked CV4031, is a special quality version of the 6J6 double triode. This valve was developed for industrial and military applications from the CV858.
The KB/D identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the D identifies the maker as Mullard Radio Valve Co., Mitcham.
The special quality valves can be identified by the use of double mica discs. These allow a longer service live in situations where the valve is subject to vibration and shock such as in vehicles and aircraft. The shaped grids pass flat across the cathode. The wire on the back of each grid has been removed.
The anodes are open rectangles and the shaping of the grids requires that they be wider than the anode.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 47 mm tall.
Reference: Data-sheet. Type 6101 was first introduced in 1963. See also1963 adverts.
