Sensibly equivalent¶ to:
The Osram N77 is a miniature audio output pentode. In single ended configuration it will produce 1.4 Watts, suitable for a small broadcast receiver.
If used in push pull an output of 4 Watts is possible, but this valve was not expected to be used for hi-fi and for a radiogram there would be sufficient space to specify a physically larger valve. Output valves in the B7G base format ran very hot and not ideal if space existed for a larger envelope.
The control grid has radiating fins.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins, is 46 mm tall.
References: Datasheet & 1040. Type N77 was first introduced in 1953.
Absolute Maximum Operating Conditions¶
Updated January 18, 2013. shape:thin.glass.tube construction:all.glass type:pentode age:1950.1960 base:b7g heater:6.3v pins:7 pin:1.g1 pin:2.k pin:3.h pin:4.h pin:5.a pin:6.ic pin:7.g2