The KTZ73 is an RF beam tetrode for RF and IF applications. It was part of the M-OV 'Uniwatt' range of valves for use with mains or vehicle lead acid batteries.
A year later in 1938 the valve became the KTZ73/6J7G RF pentode. The main differences were the heater being standardised at 6.3 Volts and making it a pentode with g3 connected to pin 5.
Above the pinch and the lower screen can be seen the bright beam plates and the inner grids. The control grid is wound on copper supports. The control and screen grids look to be aligned.
The anode and side mica rectangles that hold the electrodes tight in the shoulder of the envelope.
The top screen with a slot showing the top mica and electrode supports.
Looking up from the base: the anode is stitched together.
The classic envelope is 30 mm in diameter and, excluding the IO base pins, is 73 mm tall.
References: 1043 & 3002. Type KTZ73M was first introduced in 1937. See also1937 adverts.
