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VR35

Sensibly equivalent to:
CV1035 QP21
See also:
Quiescent Push-Pull - Some Important British Valves - Acoustic Aberation
    
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The VR35 is a British Military valve with a commercial equivalent of the M-OV QP21. The valve is directly heated and for battery HT sets. The pair of pentodes were designed to operate in Class B1 and so draw very little standing current. An important fact when the cost of HT batteries was significant. The screen grid is also common to both valves.
The presence of two distinct assemblies is clear from the picture. Also clearly visible are the filament tensioning springs.
The output power was of the order of 0.5 Watt and the anode to anode load was quoted at 25,000 Ohms.
The classic envelope is 36 mm in diameter, and excluding the B7 base pins, is 93 mm tall.
References: Datasheet & 1043. Type VR35 was first introduced in 1934.

 

Pin Connections
B7
1
2
3
4
5
6
7
g1(1)
g1(2)
a(2)
f,g3
f
g2
a(1)

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
2.0
0.4
150
120
-4.5
5.6
1.4
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated February 19, 2014.
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