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VT-104

Sensibly equivalent to:
12SQ7
See also:
The 'Magic Three' Valves
    
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The VT-104 is a double diode triode with heaters designed to operate from the 12.6 volts available in a vehicle. The VT-104 is the USA Government designation for the commercial 12SQ7.
The diodes are for AM signal detection and AGC detection whilst the triode section is for first audio amplification. This is typical for a valve used in a radio superhet receiver.
Apart from the 12.6 volt heaters the valve characteristics are equal to the 6SQ7.
The reverse of the envelope has the makers name and the country of origin.
The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 50 mm tall.
References: Datasheet & 1040. Type VT-104 was first introduced in 1939.

 

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

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
12.6
0.15
250
-2.0
0.9
91,000
1.1
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated November 24, 2013.
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