The CV1285 was previously called the NR73 before the CV register was established in 1941. The prototype for the design was the ECC31.
Type CV1285 and its other commercial equivalent the 6N7, is by no means a general-purpose double triode since it has a powerful heater, a common cathode, and is designed to operate in push-pull Class B2 with zero grid bias or quiescent push-pull. The anode to anode load is given as 8,000 Ohm.
It is specifically an audio power valve capable of 10 W per pair.
The twin triode sections with heat sinks on the tops of the control grid supports.
The control grid within the oversized anode.
The control grid heat radiating fins.
The classic envelope is 45 mm in diameter and, excluding the IO base pins is 89 mm tall.
References: Data-sheet & 1043. Type CV1285 was first introduced in 1937.