Sensibly equivalent¶ to:
The KT33C audio power output valve was introduced by M-OV in 1939 and replaced the KT33. This version had a heater centre tap and was designed for series heater chains.
For the 5 Watts output the anode load would be 3,000 Ohms. The distortion at full power is 7.5%.
The top mica shows heat radiating fins connected to the control grid. The wire running across the top of the cathode is connected to both the cathode and both beam plates.
The classic envelope is 42 mm in diameter and, excluding the IO base pins, is 100 mm tall.
References: Data-sheet & 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