The CV1246 is a battery output triode, the previous service code was the NT82.
With an anode load of 4,500 Ohms the valve can deliver 0.3 Watts. The direct commercial equivalent is the Marconi P2, a close relative is the Mullard PM202 But not the earlier Cossor P2 which is a bright emitter.
The KB/Z identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the Z identifies the maker as MO Valve Company, Hammersmith.
The bright anode has ribs pressed into it to give mechanical stability to the thin nickel sheet.
The filament is held by coiled tension springs mounted above the top mica. The filament is white as it is oxide coated.
Here the hooks on the tension springs are easier to see.
A closer view.
The classic envelope is 41 mm in diameter and, excluding the B4 base pins, is 87 mm tall.
