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The N37, N78 & CV4062 Pentodes.
The M-OV advert in the Wireless World for September, 1959 comparing valve lifetimes for standard and special quality valves gives the commercial equivalent of the CV4062 as the N78. Examination of the data for both valves brings this primary source of information into question. The CV4062 has an Ra of 23 kΩ but the same parameter for the N78 is 40 kΩ
The N78 is a 1952 audio output pentode for use on parallel heater supplies and an anode voltage typically of 250 Volts. The original prototype was called E1984.
The CV4062 traces its origins to the M-OV experimental valve E2134 that became the CV2179 and the special quality CV4062. The specification is rated for audio but it is aimed at series pass service in stabilised power supplies.
For domestic televisions with a series heater chain and lower HT voltages the N37 looks to be derived from the work with the E2134 and is specified for audio output service.
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