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7R7

Sensibly equivalent to:
CV900
    
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The 7R7 is a screened pentode and double diode. This is the classic valve design for AGC rectification, signal detection and first audio amplifier. The 7R7 pentode is of the semi variable-μ type and thus can also function for IF amplification.
The type designation is etched into the envelope dome. There is no make identified.
The wide glass tube envelope is 29 mm in diameter, and excluding the B8B base pins is 55 mm tall.
References: Datasheet & 1040. Type 7R7 was first introduced in 1942.

 

Pin Connections
B8B
1
2
3
4
5
6
7
8
h
a
a(d2)
a(d1)
g2
g1
k
h

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.3
250
100
-1
6.2
1.6
1M
2.3
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 11, 2017.
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