The P650 from Mazda is an early output triode. The design dates from 1929 and the P650 was obsolete by 1933.
The detail picture shows the grid, filaments and associated supporting structures. The anode is made of bright Nickel sheet and is equipped with additional fins. The electrode structure is not too far dissimilar from the successful power valves of the era such as PX4.
The balloon envelope is 55 mm in diameter, and excluding the B4 base pins, is 132 mm tall.
Reference: 1043. Type P650 was first introduced in 1929.
Absolute Maximum Operating Conditions¶
Updated May 26, 2018. shape:balloon construction:pinch type:triode age:1920.1930 base:b4 heater:6.0v pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f