The PCL805/85 triode pentode was purpose designed as a domestic television receiver frame output stage. The original design was the PCL85 and was improved to the PCL805. The designation PCL805/85 just indicates the interchangeability rather than another design.

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 quotes an audio output rating for the PCL805 but this was not the case for the earlier PCL85. In any case the valve of choice for audio output was the PCL86.

On the picture it can be seen that the triode is a completely separate electrode structure with an electrostatic screen between it and the power valve electrodes.

The thin glass tube envelope is 20 mm in diameter and excluding the B9A pins is 69 mm long.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	at	gt	kt	h	h	ap	g2	kp,s,g3	g1

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout
	18	0.3	170	170	-15	41	2.3	25k	7.5	3.4W

Triode	Va	Vg	mAa	ra	gm
	100	0	10	8300	1.4

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 10 June 2007 {find valves by name}