Sensibly equivalent¶ to:
Type American service Type VT-91 (commercially Type 6J7) is a contemporary of the 'Magic Three' and the design almost as ubiquitous. Although originally made as a detector its linear characteristic and good internal shielding (cf. 6Q7GT) made it a natural choice for audio.
It was for two decades the international standard valve for audio amplifier input stages and audio systems generally. The Mullard-Philips type EF37A, for many years the standard British low-noise audio pentode, is really a 6J7G under another name.
The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 62 mm tall.
References: Data-sheet, 1040 & 1043. Type VT-91 was first introduced in 1936.
Absolute Maximum Operating Conditions¶
Updated October 28, 2013. shape:thin.metal.tube construction:glass.disc 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.g3 pin:6.- pin:7.h pin:8.k pin:tc.g1