The 815 is a power double beam tetrode based on the American pattern of two separate valve sections. Operation can be as a push-pull modulator (Class AB2) or RF power amplifier. The 815 produces maximum power up to 125 MHz and at reduced ratings can operate to 175 MHz.
The twin sections with each anode brought to a top cap.
The bright metal of the beam plate can be seen at the base of the anodes.
The black top screen connects to the cathode. The heater is two hairpin loops of insulated wire. The screen grids are bridged (not seen this side). The control grid has a black U shaped radiating fin at the top and the top mica is doubled and this will provide extra resistance to vibration.
The wide glass tube envelope is 50 mm in diameter, and excluding the IO base pins is 97 mm tall.
