Sensibly equivalent¶ to:
The NR85 can be seen to be a straight rebranding of the 6F6G. In military jargon it is Naval Receiving valve number 85.
It is an output pentode designed for audio amplification in radio receivers. The operating values given are for single ended use with an anode load of 7,000 Ohms.
If a pair are used as an audio amplifier in push pull class A, 10.5 Watts are possible with 3% distortion.
The equivalent type KT63 is a beam tetrode.
The electrodes are obscured but the pinch can be seen.
The classic envelope is 42 mm in diameter and excluding the IO base pins the length is 95 mm.
References: Data-sheet, 1040 & 1043.
Absolute Maximum Operating Conditions¶
Updated April 09, 2015. shape:classic construction:pinch type:pentode age:1930.1940 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.h pin:8.k