The type Z66 was M-OV's late-1930s in-house attempt to make a small, modern high-slope pentode for wide-bandwidth IF systems in TV and radar, where bandwidths of several MHz were required. In this example the lettering is contained within the typical M-OV oval.

To ensure that the valve would be cheap and easy to make, a 'pinch' construction was used that could be assembled on existing production line machinery. Sadly the Z66 was very much a 'second best when it came to performance, particularly in terms of gain-bandwidth product and high-frequency noise figure.

The high bandwidth receiving valve that won the War was the pinchless EF50 not the Z66, even though they had comparable data-book characteristics. The extra lead length added too much inductance.

The three wire grids can be made out within the anode cavity.

The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 78 mm tall.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.63	250	250	-1.85	8	2	1.5M	7.5

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This exhibit was last updated on 25 October 2008