The classic 807 beam tetrode designated as a military valve. The ceramic base offers better insulation in humid conditions or at altitude and are scarce and keenly sought today for their aesthetic beauty as well as their exceptional performance.
The parameters given are for single ended use. When used in a class AB1 push pull pair with 600 volts on the anode an output power of 65 Watts was normal. These valves were much used in medium power amateur radio transmitters for high level modulation. In this use the output transformer, called a modulation transformer, would be impedance matched to the anode circuit of the RF power valve. The audio power would increase or decrease the amplitude of the RF envelope. The 807 was also a workhorse of the HF bands
Today, these valves find use in audio applications in classic designs from RSC to more modern new build designs.