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X147

Sensibly equivalent to:
ECH33 ECH35 X61M
    
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The X147 is an M-OV Type designation and little information can be found for it. It is given as equivalent to both the ECH33 and ECH35. The latter replacing the ECH33 in less than a year.
The interesting thing about this exhibit is that it was made for Marconiphone by Mullard and is probably an ECH35 with plain zinc paint.
Functionally it is a typical triode hexode frequency changer for broadcast receivers and the Marconiphone was a brand for domestic equipment. For maximum isolation of the signal input and output circuits the hexode control grid is taken to the top cap.
The reverse is plain.
The classic envelope is 34 mm in diameter and, excluding the IO base pins, is 91 mm tall.
References: Data-sheet, 1040 & 1043. Type X147 was first introduced in 1948.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
tc
m
h
a
g2,g4
g1(t),g3
a(t)
h
k
g1

 

Absolute Maximum Operating Conditions
Hexode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.3
250
100
-2.0
3.0
3.0
1.3M
0.65

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
3.3
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated August 24, 2021.
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