The P6 is an audio output triode for battery receivers and dates to 1933. The BA2 box referenced above is identical to the P6 box.
The P2 and P4 were electrically identical to the P6 and differ only in filament voltage. In the early days of radio 2, 4 and 6 volt accumulators were all used. This being, of course, one, two and three cells. The P2 took 0.2 Amp and the P4 0.1 Amp.
The anode load should be 6,000 Ω and the output power is 600 mW.
The bright anode seen from below. The grid and filament can be seen. The strut in the foreground goes to the glass rod that holds the filament tension springs.
The balloon envelope is 45 mm in diameter, and excluding the B4 base pins is 110 mm tall.
References: 1043. Type P6 was first introduced in 1933.
Absolute Maximum Operating Conditions¶
Updated November 11, 2012. shape:balloon construction:pinch type:triode age:1930.1940 base:b4 heater:6.0v pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f