Sensibly equivalent¶ to:
The PM stands for Philips-Mullard and were introduced in 1925. The PM2A is a later addition to the original range from 1929. The series all had oxide coated filaments.
These audio valves could drive a small loudspeaker. The PM2A had an output rating of 0.15 Watt at 5% distortion.
The balloon envelope is 43 mm in diameter and, excluding the B4 base pins, is 85 mm tall.
References: 1931 datasheet & 1043. Type PM2A was first introduced in 1930.
Absolute Maximum Operating Conditions¶
Thanks to Andy Cowley for supplying the above PDF datasheet.
Updated May 20, 2018. shape:balloon construction:pinch type:triode age:1920.1930 base:b4 heater:2.0v pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f