The ECH42 is a triode hexode mixer in an all glass envelope fitted with a B8A base and designed for radio receivers.

The base with 8 pointed pins equi-spaced around the circumference of the pin circle. A locating pip moulded into the 22 mm lower section can be seen in the centre of the picture.

See also UCH42 with a 100 mA heater for series heater chains.

The thin glass tube envelope is 20 mm in diameter, and excluding the B8A base pins is 54 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type ECH42 was first introduced^¶ in 1949.

 
Pin Connections

B8A	1	2	3	4	5	6	7	8
	h	a	a(t)	g1(t),g3	g2,g4	g1	k	h

 
Absolute Maximum Operating Conditions^¶

Hexode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.23	250	85	-2.0	3.2	3.75	1.0M	0.71

Thanks to Frank Philipse for supplying the above PDF datasheet