The QV05-25 from Mullard is another example of the design known as the 807. The QV05-25 is a beam tetrode.

The parameters given are for single ended use. When used in a class AB1 as a push pull pair with 600 volts on the anode an output power of 65 Watts was normal.

The QV05-25 was an HF RF amplifier and used in many designs in the 1950s. As a transmitter power amplifier (shown in the lower table) operating in class C producing 40 Watts of RF, it would need a pair of 807s in push pull to generate the 20 Watts of audio required to fully modulate the valve.

The side view shows the bow screening plates below the anode that is a distinctive feature of the *)& type of valve.

The classic envelope has a maximum diameter of 50 mm and a length, excluding the UX5 base pins, to the tip of the top cap of 128 mm.

 
Pin Connections

UX5	1	2	3	4	5	tc
	h	g2	g1	k	h	a

 
Absolute Maximum Operating Conditions

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout
	6.3	0.9	300	250	-14	83	8	20k	6.5	6.7W

Beam Tetrode

Vh

Ah

Va

Vs

Vg

mAa

mAs

mAg

Pdriv

Pdiss

Pout

freq

f.max

6.3

0.9

600

250

-45

100

7

3.5

0.2W

25W

40W

60

125

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 10 June 2007 {find valves by name}