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: Data-sheet, 1040 & 1043. Type 6B8 was first introduced in 1937. See also 1937 adverts.
Absolute Maximum Operating Conditions¶
Updated January 28, 2013.