VT-131 @ The Valve Museum

▼ Menu

Home Search Indexes Equivalents Articles Adverts & Boxes Timeline Collections Donate Contact

VT-131

Sensibly equivalent^¶ to:

12SK7

Extras ▼

Ken-Rad The Signals Museum - RAF Henlow. Other VT-131 exhibits

The VT-131 (commercially the 12SK7) is a variable μ pentode for RF and IF amplifiers in superhet receivers. The gain of the device being controlled by a negative voltage derived from rectifying the final IF signal. In this way strong signals do not overload the receive chain because the various controlled stages have their gain reduced.

The 12.6 Volt heater was introduced so that the heater could be run directly from a vehicle battery. It would have been common to find these valves in professional mobile equipment. For fixed station use the 6SK7 was an identical device in all other respects.

The Ken-Rad maker's name. The SC961A is a military inspector stamp.

The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 51 mm tall.

References: Data-sheet, ⁴⁰⁵⁵, ³⁰⁰² & ¹⁰⁴⁰. Type VT-131 was first introduced in 1939. See also 1939 adverts.

Pin Connections

IO	1	2	3	4	5	6	7	8
	m	h	g3	g1	k	g2	h	a

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	12.6	0.15	250	100	-3	9.2	2.6	0.8M	2.0,

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated September 10, 2024.

Return to Main Index