Sensibly equivalent¶ to:
The CV4006 is the UK government procurement specification for the commercial 6059 which is itself a special quality version of the type 6BR7. The specification gives the prototype as the VX7081. The valve was carefully designed for low internal noise and, especially, for low internal hum pick-up from the 6.3V AC heater, thus making it unnecessary to provide a DC source of heater current.
Haltron is the brand name of Hall Electric and their valves were for export from the UK.
The view along the grids, the grids themselves are obscured.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 47 mm tall.
References: Datasheet & 1040.
Absolute Maximum Operating Conditions¶
Updated November 12, 2013.