Sensibly equivalent¶ to:
4074B CV1573 TV03-10
The VT61A transmitting double triode was designed for use up to 150 MHz. It was made by Rogers of Canada and carries the Air Ministry markings. The VT prefix is an Air Force designation.
The operating parameters, but not the heater values, given are from the 4074A and this was a UX7 based valve as this is the closest match to the VT61A we could find. The 4074B is a B5 based valve of pinch construction in a classic glass envelope. The anodes are brought out to separate top caps.
Triodes were favoured for transmitter work over tetrodes because of lower capacitances and an ability to be driven harder. This valve was designed to pass a grid current of 17 mA.
The classic envelope is 46 mm in diameter and, excluding the B5 base pins, is 110 mm tall.
Absolute Maximum Operating Conditions¶
Updated January 24, 2017. shape:classic construction:pinch type:double.triode age:1940.1950 base:b5 heater:12.6v pins:5 pin:1.g1(1) pin:2.g1(2) pin:3.h pin:4.h pin:5.k pin:tc.a(1) pin:tc.a(2)