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HL41DD

Sensibly equivalent to:
CV2996
See also:
Ediswan Valve Advert - Murphy Radio
    
Extras ▼

 

The Mazda HL41DD is a mains operated double diode triode for use in superhet receivers as detector, AGC rectifier and first audio voltage amplifier. The HL41 is a single triode.
The HL41DD was used in the 1948 Murphy television receiver V114 as the sound second detector and first audio amplifier.
The four Volt heater was the UK standard for indirectly heated AC valves in the 1930s.
The reverse is plain metallic paint.
The classic envelope is 32 mm in diameter, and excluding the base pins is 89 mm tall.
References: Datasheet, 1040 & 1043. Type HL41DD was first introduced in 1938.

 

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

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
μ
4.0
0.65
250
-1
3.2
12,000
2.5
20.0
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated October 17, 2018.
shape:classic construction:pinch type:double.diode.triode age:1930.1940 base:mo heater:4.0v pins:8 pin:1.h pin:2.k pin:3.a pin:4.- pin:5.a(d2) pin:6.m pin:7.a(d1) pin:8.h pin:tc.g1
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