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VMS4B

Sensibly equivalent to:
AC/SGVM AS4125 CV1165 MVSPen VP4
See also:
Marconi Advert, March 1935 - M-OV's Screened Grid Valves
    
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The type VMS4B typifies the swansong of the screen-grid receiving valve with anode top cap. It is an improved, vari-mu RF/IF tetrode intended for domestic superhet receivers but it represents the final milestone on the road which started (barely 10 years earlier) with the Type S625.
VMS4B features a straight tube above the base to facilitate through chassis mounting. This exhibit is later after it was found that such screening was not required. The envelope widens out immediately abve the base.
The Marconi branding of this M-OV valve. Note the internal bright gettering under the external zinc screening paint.
The classic envelope is 44 mm in diameter and, excluding the B5 base pins, is 108 mm tall.
References: Datasheet & 1005 Type VMS4B was first introduced in 1933.

 

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
gm
4.0
1.0
200
80
0
8.0
1.5
2.9
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated September 09, 2013.
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