The 813 is a American design and is a high voltage, low current beam tetrode. This exhibit was made in Canada and is badged Marconi.

The 813 is one of the largest valves used in HF amateur radio. Classic amplifier designs from the late 1950s would squeeze 1000 Watts PEP from a single device for SSB use. In class AB2 the input power for AM or CW would be 500 watts.

The valve base would be mounted on spacers so that a blower could be fitted under the chassis and a stream of forced air cooling would pass over the envelope.

The classic envelope is substantial at 60 mm diameter and 170 mm long excluding the special base pins. The anode is 53 mm long and 48 mm wide. The metal is 1 mm thick.

 
Pin Connections

	1	2	3	4	5	6	7
	f	nc	g2	g1	bp	nc	f

 
Absolute Maximum Operating Conditions

Beam Tetrode	Vh	Ah	Va	Vs	Pdiss
	10	5	2500	800	125W

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}