The Mazda 6C12 triode heptode was designed for the role of frequency changer (mixer) in superhet receivers. This double valve has a common cathode. The triode is to be used as the local oscillator feeding the 13 Volts pk-pk amplitude sine wave to the heptode mixer.

The reverse side shows the made in England lettering.

A close-up on the valve reveals that the triode is mounted above the heptode section. The triode grid can be seen through a hole in the outer screen.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 57 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	g2,g4	g1	k,g5,s	h	h	a	g1	a(t)	g1(t)

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	mAa
	6.3	0.3	100	13

Heptode	Va	Vs	Vg	mAa	mAs	ra	gm
	250	250	-2	6.5	3.8	0.7M	0.775

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 04 July 2009