The CV4002 is the flying lead version of the CV4014 and we believe that the CVX4002 is a variant but have not been able to confirm this. The following refers to the CV4002.
Electrically it is an M8083 or 6064. These are both designations for the special quality version of the EF91 (CV138).
The special quality version has a more rugged build than the EF91 and was designed for operation in areas of vibration especially aircraft.
The KB/FB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FB identifies the maker as STC, Footscray.
The anode consists of two small plates joined by an integral strap. Within are three wire grids.
The control grid has copper supports. Comparing this exhibit with an STC CV4002 the difference appears to be the presence of a plastic (PTFE?) spacer between the envelope and the lead wires.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 45 mm tall.
Reference: Data-sheet. Type CVX4002 was first introduced in 1953. See also1953 adverts.
