The 809 is a directly heated power triode with a thoriated tungsten filament and an anode dissipation of 30 Watts.
As a Class C PA the output can be up to 55 Watts. A pair used as a Class B audio modulator can give an output approaching 145 Watts.
The valve was made in USA and the ceramic insulators are required due to the high voltages employed.
The RCA logo on the base cap.
The lower ceramic insulator and within the anode the grid can be seen to be close wound.
The top insulator with mica disc above. The anode is made of pressed nickel sheet. The filament tension springs can be seen but the hooks and filament are not visible.
Top view of the tensioning springs.
The classic envelope is 60 mm in diameter and, excluding the UX4 base pins, is 146 mm tall.
Reference: Data-sheet. Type 809 was first introduced in 1946. See also1946 adverts.
