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VR99A

Sensibly equivalent to:
10E/757 CV1581 ECH35
    
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The VR99A is a triode hexode, and the VR denotes that it was designated for use with the RAF as a receiver device.
The triode was designed for local oscillator use and an injection voltage of 10 V peak to peak was produced. The hexode mixer took the signal into the top cap grid, thus maintaining the greatest separation between grid and anode circuits.
The VR99 was selected from X65 production and given the Type designation of X66. The VR99A, later renamed CV1581 was a clear envelope triode hexode and based on the Mullard ECH35.
The classic envelope is 37 mm in diameter and, excluding the IO base pins, is 94 mm tall.
References: Datasheet & 3002. Type VR99A was first introduced in 1940.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
tc
m
h
a
g2,g4
g1(t),g3
a(t)
h
k
g1

 

Absolute Maximum Operating Conditions
Hexode
Vh
Ah
Va
Vs
Vg
mAa
ra
gm
6.3
0.3
250
100
-3
1.75
2.5M
0.225

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
4.75
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated April 26, 2013.
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