Sensibly equivalent¶ to:
The QP22B is a wonderful valve. It is a battery double pentode, designed for quiescent push pull class B audio amplification. The total power output is 1 Watt and was aimed at driving a loudspeaker, quite a luxury when battery powered.
The valve can be operated with automatic bias obtained from a resistor in the common HT negative lead. Such a resistor should be bypassed at signal frequencies by a 50 µF capacitor. For minimal distortion the total anode current (both anodes) should not fall below 3 mA and the screen grid supply should be 120 Volts.
The classic envelope is 38 mm in diameter and, excluding the B7 base pins, is 94 mm tall.
References: 1043. Type QP22B was first introduced in 1938.
Absolute Maximum Operating Conditions¶
Updated December14, 2012. shape:classic construction:pinch type:double.pentode age:1930.1940 base:b7 heater:2.0v pins:7 pin:1.g1 pin:2.g1 pin:3.a pin:4.f pin:5.f pin:6.g2 pin:7.a