The ARP38 is a 1937 RF beam tetrode for RF and IF applications. As the KTZ35 it was part of the M-OV 'Uniwatt' range of valves for use with mains or vehicle lead acid batteries. It was only supplied with external metal paint. This exhibit has lost the paint.
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.
This exhibit has no Type designation visible but the shape is distinctive.
The only visible marking is this 35P62. If originally this valve was covered in metallic paint, the Type would have been presented on the outer surface.
Below the anode and above the mica can be seen the wire of the two outer grids.
The classic envelope is 30 mm in diameter and, excluding the IO base pins, is 73 mm tall.
