The MVSG from Cossor has a mirror finish inside the envelope from the magnesium gettering. Externally the envelope is covered with a metallic paint to add to overall screening.

Introduced in 1932, Cossor in 1935 describe the MVSG as a special variable-mu screened grid valve. The special feature being the control of volume by altering the grid bias. It is clear that variable-mu technology was still relatively novel.

The classic envelope is 42 mm in diameter and, excluding the B5 base pins, is 120 mm tall.

 
Pin Connections

B5	1	2	3	4	5	tc
	g2	g1	h	h	k	a

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	4.0	1.0	200	80	-1.5	7.5	0.75	0.2M	2.5

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 02 December 2007 {find valves by name}