The CV4086 is the flying lead version of the M8195 = CV4085 that is the special quality version of the Mullard EF86 early stage audio pre-amplifier valve. The CV specification used the CV2901 as the prototype.
Mullard recommend that the EF86 is fitted into an anti-microphonic base. This usually means a base where the fixing flange is a synthetic rubber structure. In this valve the flying leads are designed for direct soldering into a circuit. A rigid fixing used with valves of high reliability.
Looking through the mesh outer screen the anode can be seen as two sides of a cylinder with a strap replacing metal outside the grid supports. Thus the electrons are collected from the straight line path from cathode, through grids to anode.
The base. The pins are formed from three sections as normal with the top as stiff rods to weld the electrodes to, the centre section is an alloy with an expansion co-efficient that closely matches the glass foot and the outside part is replaced with a long wire. Care is required to avoid bending the leads too close to the glass as this can cause the glass to fracture.
The thin glass tube envelope is 21 mm in diameter and excluding the B9A base pins, is 49 mm tall.
Reference: Data-sheet. Type CV4086 was first introduced in 1959. See also1959 adverts.