This PCL86 was made in the UK by Mullard and was designed for the audio stage of a television receiver and offered a quality output.

In 1961 Mullard developed a combination of an ECC83 triode and an EL84 output pentode in a single envelope and this was the ECL86. The PCL86 was the series heater chain version of that work.

The separate triode section would provide the first audio amplification, and the output pentode would drive the loudspeaker.

The PCL86 as a single ended audio amplifier would have a cathode resistor of 125 Ohms and an anode load of 5,100 Ohms and under these conditions would produce an output power of 4.1 Watts at a distortion of 10%.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 70 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type PCL86 was first introduced^¶ in 1961.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	g1(t)	k(t)	g2	h	h	a	k,s,g3	g1	a(t)

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	13.3	0.3	230	230	-5.7	41.0	10.5	16,000	7.5

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	13.3	0.3	230	-1.7	1.2	62,000	1.6

Thanks to Frank Philipse for supplying the above PDF datasheet

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