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AC/SGVM

Sensibly equivalent to:
AS4125 AS4125 CV1165 MM4V MVSPen VMS4B VP4
See also:
Mazda Variable-mu Valves Advert
    
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The AC/SGVM is a variable μ RF tetrode. Initially when released it had a balloon envelope and plastic top cap with screw connection see DC2/SGVM. This exhibit is later and has the top hat top cap and shouldered envelope. It is also fully screened with external metalisation.
The Mazda Valve Manual from 1935 describes the AC/SGVM (and AC/S1VM) as available for replacement purposes. The pentode had taken over from the screened grid valve in their current designs. Their text reads:-
These valves are of the Variable-mu type, solely for use in receivers where volume is controlled by potentiometer adjustment of grid bias. Their characteristics are such that, with increase of negative control-grid voltage, anode current and mutual conductance characteristics follow a shape which minimises cross modulation and amplitude distortion.
The reverse is plain zinx paint.
The classic envelope is 39 mm in diameter, and excluding the B5 base pins is 110 mm tall.
References: 4022, 1040 & 1043. Type AC/SGVM was first introduced in 1932.

 

Pin Connections
B5
1
2
3
4
5
tc
g2
g1
h
h
k
a

 

Absolute Maximum Operating Conditions
Tetrode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
4.0
1.0
200
60
-2
5.0
0.9
0.7M
2.0
Updated April 01, 2014.
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