The EK3 octode frequency changer is set on the short lived side contact base. The local oscillator formed using a grid as anode would need to supply 17 volts peak to adequately modulate the main electron flow. The signal input to g4 is applied to the top cap for maximum circuit isolation. The frequency of use would be a few megahertz at best.

Our other EK3 has a much greater diameter envelope and is probably a later product. Clearly this valve has overheated in use.

The wide glass tube envelope is 33 mm in diameter and, excluding the Ct8 base pins, is 124 mm tall.

 
Pin Connections

Ct8	1	2	3	4	5	6	7	8	tc
	m	h	h	k	g2	g1	g3,g5	a	g4

 
Absolute Maximum Operating Conditions

Octode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.65	250	100	-2.5	2.5	5.5	2M	0.65

Thanks to Frank Philipse for supplying the above datasheet

More

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