Sensibly equivalent¶ to:
The 6B8 American metal valve is a double diode pentode. Such valves were made for the signal detector, AGC detector and first audio amplifier stages of superhet receivers usually as a double diode triode. This valve with a vari-μ pentode offered the set designer the option of using this as final IF stage plus detectors. For local reception a pentagrid converter (heptode), this valve and sensitive output valve may have been all that was required apart from a rectifier.
The 12C8 is electrically identical but has a 12 volt heater.
The thin metal tube envelope is 24 mm in diameter and, excluding the IO base pins, is 62 mm tall.
References: Datasheet, 1040 & 1043. Type 6B8 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated January 28, 2013. shape:thin.metal.tube construction:glass.disc type:double.diode.pentode age:1940.1950 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.a(d2) pin:5.a(d1) pin:6.g2 pin:7.h pin:8.k pin:tc.g1