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QP25

Sensibly equivalent to:
ARP37 CV556 CV1342
See also:
Quiescent Push-Pull
    
Extras ▼

 

The QP25 is a pre-war quiescent push-pull double pentode for battery operation. It was still listed as current production in 1951.
QPP valves operated in class B and for a 19 Volt peak to peak input signal the QP25 would deliver 1.1 Watt output at 5% distortion. See also QP230.
One anode seen from the front. The three central connections are to the filament. The filament passes through the anode four times in an M shape.
The dome carries the identification. Above the top mica are the filament tension springs. The suppressor grid and screen grid of the top section can be seen.
The single lower mica holds both pentode sections. Note the parallel connections to the filaments.
The classic envelope is 32 mm in diameter, and excluding the MO base pins, is 73 mm tall.
References: Datasheet & 1043. Type QP25 was first introduced in 1939.

 

Pin Connections
MO
1
2
3
4
5
6
7
8
f-
-
a(2)
g2
g1(2)
g1(1)
a(1)
f+

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
Pout
2.0
0.2
120
120
-9.75
2.3
0.43
1.2W
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated October 14, 2018.
shape:classic construction:pinch type:double.pentode age:1930.1940 base:mo heater:2.0v pins:8 pin:1.f- pin:2.- pin:3.a(2) pin:4.g2 pin:5.g1(2) pin:6.g1(1) pin:7.a(1) pin:8.f+
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