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Pen4VA

Sensibly equivalent to:
7A2 A70B AC/Pen APP4A CV1174 KT42 MKT4/7 MP/Pen N40 P4VA
See also:
Mullard AC Mains Valves - CV1174 short entry
    
Extras ▼

 

The Pen4VA was, eventually, the Mullard answer to the landmark Mazda AC/Pen of 1930 for audio output within AC mains sets. The photo shows a post-war specimen made for replacement purposes. Following a series of rather less successful attempts to make indirectly-heated output pentodes (Pen20) the successful but obsolescent Pen4BA was introduced with a B7 base cap (by then, after 1933, current) but Pen4VA B5 versions were supplied as replacements for its less successful predecessor the Type Pen4V. These were designated Pen4VA (5).
The original valve took 12 mA of screen current. The revised version of 1937 reduced this to 3.0 mA and with a cathode resistor of 500 Ω and a 6 kΩ load produced 3.8 Watts as opposed to the original 3.4 Watts.
The image shows a mesh anode with wire grids and oxide coated cathode. The construction uses a glass rod for support whereas later designs will adopt the classic (or shouldered) envelope and mica supports.
Thanks to Peter Lawn for the image.
The Balloon envelope is  mm in diameter, and excluding the B7 base pins, is  mm tall.
References: Private communication, 1043 & 4024. Type Pen4VA was first introduced in 1933.

 

Pin Connections
B7
1
2
3
4
5
6
7
-
g1
g2
h
h
k,h3
a

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
rk
rl
Pout
D
4.0
1.35
250
250
-20
36
3.0
40,000
2.8
500
6,000
3.4W
10%
PDF scanned from an original document held by the museum
Updated April 07, 2015.
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