The V1505 is a power triode for audio or RF amplifier use up to 1.5 MHz. These valves would have been found in medium power transmitters for long wave and medium wave service. A pair operating in push pull can generate 800 Watts of audio to modulate an AM power valve. Note that this valve is also marked 14D13
The thoriated tungsten filament has substantial thickness. The maximum emission is a peak of four Amps. Note the strong springs to maintain tension and therefore inter-electrode geometry as the filament expands on heating.
The carbon anode.
The anode and within it the grid.
The grid is shaped to provide a flat travel parallel to the anode across the filament strands.
The valve is constructed with a glass disc base to improve the HF characteristics by reducing lead length and thus inductance.
The anode is held in place by crimp fixings over the support rods. The grid is conventional in being wound into notches on the support wires.
The base pins are held in place within a ceramic support.
The wide glass tube envelope is 90 mm in diameter, and excluding the base pins is 285 mm tall.
Reference: Datasheet. Type V1505 was first introduced in 1961.