The 6B8G double diode amplifier pentode was designed for detector and first audio stages in radio receivers. The diodes would be for signal and AGC detection and the high impedance audio pentode would provide good small signal gain for feeding into an output pentode.

The upper part of the valve is the screen pentode and below the circular screen can be seen one of the diode anodes.

The classic envelope is 38 mm in diameter and, excluding the IO base pins, is 96 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	m	h	a	a(d2)	a(d1)	g2	h	k	g1

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	125	-3	9	2.3	0.6M	1.12

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 10 May 2009