The PCL805 triode pentode was purpose designed as a domestic television receiver frame output stage for monochrome sets and on rare occasions (ITT CVC5 chassis) colour sets. As is common with TV valves it is designed to operate at a relatively low voltage and high current. The beam tetrode has a quoted load resistance of 4,000 Ohms.
The literature gives ratings for audio service but the PCL86 was the normal audio stage valve.
The tiny triode can be seen on the right. Both of the inner grids have copper supports and are topped by radiating fins.
With the output valve on the right the bright plate is the electrostatic screen.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A pins is 70 mm tall.
References: Data-sheet & 3002. Type PCL805 was first introduced in 1968. See also1968 adverts.