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TH62

Sensibly equivalent to:
ECH35
    
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The TH62 is a triode hexode frequency changer that differs from the ECH35 and CCH35 in that the heater is 6.3 V at 0.2 Amps whereas the CCH35 for series heater chains is 7.0 Volts at 0.2 Amps and the ECH35 for parallel heater chains is 6.3 Volts at 0.3 Amps.
Operationally is a typical triode hexode frequency changer or mixer for broadcast applications. The exhibit has the Mullard gold paint external metallisation and for maximum isolation of the signal input and output circuits the hexode control grid is taken to the top cap.
See CV1581 for the clear ECH35.
The reverse is plain screening paint. The fabric insulation tape is there to secure the envelope to the base as the cement has failed.
The classic envelope is 35 mm in diameter and, excluding the IO base pins, is 92 mm tall.
References: Data-sheet, 1040 & 1043. Type TH62 was first introduced in 1939. See also 1939 adverts.

 

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
0.2
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 March 08, 2026.
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