This VP22 from Mazda has lost its outer metalisation. This interestingly reveals a label affixed to the glass envelope.
The VP22 is a directly heated battery variable-mu pentode and features the Mazda Octal base. The MO base was established as a rival to the American International Octal base.
The classic envelope is 31 mm in diameter, and excluding the MO base pins, is 83 mm tall.
References: Data-sheet, 1040 & 1043. Type VP22 was first introduced in 1938.
Absolute Maximum Operating Conditions¶
Updated February 02, 2013. shape:classic construction:pinch type:pentode age:1930.1940 base:mo heater:2.0v pins:8 pin:1.f pin:2.- pin:3.a pin:4.g2 pin:5.g3 pin:6.m pin:7.- pin:8.f pin:tc.g1