The QQV03-20A from Mullard is a double beam transmitting tetrode.

Following the European pattern, a central flat cathode is surrounded by a split control grid (one half per valve), a common screen grid is wound next. The two beam forming plates can be seen either side of the central assembly. The anodes are finned for good heat dissipation and clearly separated from the central structures, the anodes are brought out to pin like top caps.

The heater runs at 6.3 volts when both halves are in parallel or 12.6 volts when in series. For 6.3 volts pins 4 & 5are connected together with pin 2 as the other end. For 12.6 Volt operation the voltage is connected to pins 4 & 5 with pin 2 left unconnected.

In addition to use as transmitter power amplifiers the upper frequency of 600MHz made them popular for frequency multiplication.

See also QQV03-20.

The wide glass tube envelope is 44 mm in diameter and, excluding the B7A base pins and top pins is 50 mm tall.

 
Pin Connections

B7A	1	2	3	4	5	6	7	tc	tc
	h	g1(2)	g2	k,bp,s	htap	g1(1)	h	a(1)	a(2)

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	mAg	Pdriv	Pout	Pdiss	freq	f.max
	6.3	1.3	600	250	-60	100	8	1.4	1.5W	48	20W	200	600

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 21 October 2008 {find valves by name}