The 8B10, for series heater chains, and the 6B10, for 6.3 Volt parallel heaters, are multi valves of the Compactron series. In this case the envelope contains two triodes and a pair of signal diodes.
The makers printed identification with one of the triodes behind. Both triodes are identical and have copper grid supports.
From left to right: triode 1, triode 2, screen and the twin diodes with anodes in vertical X formation on a common cathode.
The diodes with screen behind.
A clearer view of the cylindrical diode anodes.
The face of the outer triode.
Below the lower mica. The insulated heater can be seen looping from section to section.
The wide glass tube envelope is 28 mm in diameter, and excluding the B12C base pins is 38 mm tall.
Reference: Data-sheet. Type 8B10 was first introduced in 1961. See also 1961 adverts.
Absolute Maximum Operating Conditions¶
Updated February 06, 2015.