The 703A is a power triode for generating RF at up to the UHF region.
The filament runs vertically and is held under tension by a spring arm. The anode is finned and semi-circular at the apex of the triangular fins. The grid is helical and held to a vertical support opposite the open end of the anode.
A Japanese company (Yamamoto Sound Craft Corp) has, in 2012, offered new bases for these valves and suggested their use for audio. With an anode load of 5,000 Ω HT of 377 Volts, grid at -21.6 Volts setting a current of 37 mA an output of 1 Watt is claimed.
The balloon envelope, also known as a doorknob, is 50 mm in diameter and, including the special base pins, is 41 mm tall.
Absolute Maximum Operating Conditions¶
Updated December03, 2012.