The VP4B is a variable μ pentode for RF and IF amplifier use. The VP4 was introduced by Mullard in 1933, the B variant being introduced in 1935.

This exhibit typifies the pentode challenge to the screen-grid in the second IF position of cheaper superhets. Although not the equal of the (then) latest American types, it audibly outperformed screen-grids such as the VMS4B when the radio was sited close to the transmitter. Note the style of marking and the texture and light colour and of the gold spray paint. These are characteristic of Mullard production immediately before WW2.

The classic envelope is 40 mm in diameter and, excluding the B7 base pins, is 100 mm tall.

 
Pin Connections

B7	1	2	3	4	5	6	7	tc
	m	a	g3	h	h	k	g2	g1

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	4.0	0.65	250	250	-3	11.5	4.25	-	2.0

This exhibit was last updated on 02 December 2007