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A70D

Sensibly equivalent to:
PenA4
    
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The A70D is an audio output pentode that when working into a load of 8,000 Ohms will produce 3.8 Watts.
Ever Ready are best known for making dry batteries but did at one time make their own valves. However, the majority of Ever Ready valves were made by Mullard, a fact not generally known at the time. The A70D is the PenA4. The shape of the A70D matches the post war PenA4.
The top mica is all that is visible. Note the copper supports for the control grid with radiating fin.
The classic envelope is 44 mm in diameter, and excluding the B7 base pins is 115 mm tall.
References: 1043 Type A70D was first introduced in 1936.

 

Pin Connections
B7
1
2
3
4
5
6
7
-
g1
g2
h
h
k
a

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
4.0
1.95
250
250
-5.8
36
5.0
Updated December14, 2012.
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