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MX40

Sensibly equivalent to:
15A2 41MPG A80 A80A CV3576 FC4 FCH MH4105 VHT4 X42
See also:
Pentagrid Converters
    
Extras ▼

 

The MX40 is a 1934 Osram frequency changer of heptode construction and some of the grids are clearly visible in the picture.
The British radio industry was slow in adopting the superhet for a variety of reasons one of which was that British valve manufacturers were slow in developing the specialised types of valve required in an efficient, low-cost set.
The American radio industry showed the way and the MX40 is simply a home-brewed copy of the American 'pentagrid converter' frequency changers popular there in the early 1930s.
The oscillator voltage was designed to be 10.0 V peak to peak.
The balloon envelope is 43 mm in diameter and, excluding the B7 base pins, is 115 mm tall.
References: Datasheet, 1040 & 1043. Type MX40 was first introduced in 1934.

 

Pin Connections
B7
1
2
3
4
5
6
7
tc
g2
g1
g3,g5
h
h
m,k
a
g4

 

Absolute Maximum Operating Conditions
Heptode
Vh
Ah
Va
Vs
Vg
gm
4.0
1.0
250
80
-3
0.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated December13, 2012.
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