The CV72 is an output tetrode for pulse service. Designed to produce pulses of 10 μs duration and at a repetition rate of 400 pulses per second.
The E on the envelope probably identifies the maker as Thorn-AEI, Brimsdown - Enfield London.
The CV73 is essentially the same valve but with different connections and a four Volt heater.
The anode has side flanges for both support fixings and extra radiating surface area.
Here the flat sides of the screen grid are easy to see, a bit harder to see is the winding of the control grid, however on the left side the flat wires are visible and on the right the shape is clear as having a slight outwards bow.
The flat central cathode and bright beam plates. The heater wires that one can see are folded within the cathode to form four vertical passes.
A closer view.
The classic envelope is 54 mm in diameter, and excluding the B7base pins is 119 mm tall.
