The 6SR7 is a double diode triode sharing a common cathode. This triple sectioned valve was designed for superhet AM receivers. The first diode acts as signal detector feeding the audio signal via a volume control into the triode AF amplifier before the signal passes to the audio output valve. The second diode produces a DC voltage that is directly proportional to the audio signal and this voltage is used to control the gain of IF and RF stages of the receiver.

Compared to the pin compatible 6SQ7 this valve would exhibit lower gain in the triode stage.

The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 50 mm tall.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.3	250	-2	0.9	91K	1.1

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 01 November 2008 {find valves by name}