The 6F7B is a variant of the 6F7 triode pentode mixer. The triode oscillator has to generate 7.0 Volts pk-pk to drive the mixer section.

Both sections share a common cathode. The screened upper cylinder is the pentode mixer. The small bright tab below is the triode anode. Under a glass the triode grid can be seen. The cathode tube is oxide coated only along the length of each anode, above the triode anode the tube is un-coated.

The classic envelope is 38 mm in diameter, and excluding the UX7 base pins is 103 mm tall. Type 6F7B was first introduced^¶ in 1940.

 
Pin Connections

UX7	1	2	3	4	5	6	7	tc
	h	a	g2	a(t)	g1(t)	k	h	g1

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	100	-3.0	2.8	0.6	2M	0.3

Triode	Va	Vg	mAa
	100	-	2.4