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MHL4

Sensibly equivalent to:
154V 164V 41MLF CV1038 CV3547 NR26 VR38
See also:
CV1038 short entry - Valves for Superhets - Adding AVC to the Monodial Super - The New Monodial Super - Quality Push-Pull Amplifier
    
Extras ▼

 

The MHL4 was used in professional and military applications over many years until it was superseded by the L63, which had comparable characteristics. We have an earlier example MHL4 with a balloon envelope.
The Osram paper label.
Through the top one can see the three insulated heater loops and the grid supports.
looking up from the base the pinch can be seen and above the rectangular lower mica. The anode is a plain grey rectangle.
The classic envelope is 44 mm in diameter and, excluding the B5 base pins, is 95 mm tall.
References: Data-sheet, 1040 & 1043. Type MHL4 was first introduced in 1929. See also 1929 adverts.

 

Pin Connections
B5
1
2
3
4
5
a
g1
h
h
k

 

Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
ra
gm
4.0
1.0
250
-8
8.0
8,000
2.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated June 04, 2023.
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