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OM5C

Sensibly equivalent to:
OM5B
    
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The OM5B from Cossor is, according to Thrower, the Mullard EF37A design of RF Pentode. The OM5C is essentially the OM5B but suitable for use in DC amplifiers. The ratings given match the EF37A exactly.
The EF37A became a very respected low noise audio pre-amplifier valve that was replaced by the B9A EF86.
The reverse of the envelope is plain zinc paint.
The classic envelope is 30 mm in diameter, and excluding the IO base pins is 84 mm tall.
References: 1040 & 1043. Type OM5C was first introduced in 1940.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
m
h
a
g2
g3
nc
h
k

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.2
250
100
-2
3
0.8
2.5M
1.8
Updated April 30, 2014.
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