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ID = 11581
Great Britain (UK)
Brand: Mullard Radio Valve Co. Ltd.;
Tube type:  Double Pentode   Power/Output 
Identical to QP22A = BLL32 = K77A
First Source (s)
1935 : -- Original-techn. papers.

Base B9 British 9-Pin (Codex=Yx)
Was used by Radio/TV-reception etc.
Filament Vf 2 Volts / If 0.45 Ampere / Direct / Battery =

Announced in the 1935 Data book of Mullard.

Each section of the valves are graded with the letters P,Q,R,S, or T. etched on the glass above pins 2 and 7 which identify the two halves. This enables screen voltages in the range 103.5 to 133.5 to be selected to achieve a balance between the two sections without the need to measure the anode currents.

Information source History of the British Radio Valve to 1940   p. 142 & 188
- - Manufacturers Literature   Mullard 1935
Babani, International Radio Tube Encyclopaedia
Taschenbuch zum Röhren-Codex 1948/49

s_485_g.gif QP22A: W.Sprick: Austausch-Röhren-Lexikon 1947
Günther Stabe † 19.8.20

Just Qvigstad
QP22A: Mullard Valves 1936
Peter Hoddow

Usage in Models 1= 1935?? ; 2= 1937

Quantity of Models at with this tube (valve, valves, valvola, valvole, válvula, lampe):3

Collection of



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