Mullard describe the CL33 as a high sensitivity output pentode for use in DC/AC mains operated equipment. The CL4 is electrically identical but is fitted onto a Ct8 base.

This audio power pentode works into an anode load of 4300 Ohms and was designed to have its heater fed as part of a chain from the mains. Such valves were used in universal radio receivers and television sets. The anode voltage of 200 Volts is a clear indication of a design for use on european mains voltages.

The internal metalisation hides the electrode structure.

The classic envelope is 46 mm in diameter and, excluding the IO base pins, is 108 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8
	m	h	a	g2	g1	-	h	k

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm	Pout
	35.0	0.2	200	200	-7.5	45	5	8	3.2W

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 05 July 2007 {find valves by name}