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DT41

Sensibly equivalent to:
TDD4
    
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E K Cole made radio receivers at their factory in Southend on Sea, Essex and are famous for their innovation of bakelite cabinets. The DT41 carries the Ekco brand but was not made by them. The DT41 is a direct equivalent of the Mullard TDD4 as it was made, we believe, by Mullard for Ekco.
As a double diode triode the DT41 was designed for superhet receivers and served as detector, AGC rectifier and first audio voltage amplifier.
The metal paint obscures the electrodes but through the top of the glass the top mica can be seen. Under strong light the anode can be seen as a pressed and blackened rectangle with a rounded centre for the grid. The latter is fitted with a small radiating fin that is connected to the top-cap with copper wire.
The classic envelope is 42 mm in diameter, and excluding the B7 base pins is 111 mm tall.
References: Datasheet, 1043 & 3002. Type DT41 was first introduced in 1937.

 

Pin Connections
B7
1
2
3
4
5
6
7
tc
a(d2)
m
a(d1)
h
h
k
a
g1

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
4.0
0.65
250
-7
4.0
13,500
2.0
PDF scanned from an original document held by the museum
Updated December23, 2012.
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