Sensibly equivalent¶ to:
The KT33C audio power output valve was introduced in 1939 and replaced the KT33. This version had a heater centre tap.
For the 5 Watts output the anode load would be 3,000 Ohms. The distortion at full power is 7.5%.
The mutual conductance is given as 10, this suggests a very small gap between the cathode and the control grid, in turn implying very tight manufacturing tolerances.
The classic envelope is 42 mm in diameter and, excluding the IO base pins, is 100 mm tall.
References: Datasheet & 1043. Type KT33C was first introduced in 1939.
Absolute Maximum Operating Conditions¶
Updated May 19, 2014. shape:classic construction:pinch type:beam.tetrode age:1930.1940 base:io heater:300ma pins:8 pin:1.hct pin:2.h pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.h pin:8.k