Valve Gallery -
Triode Amplifiers (1)
AC/HL, MH4, MHD4.
|Shown above is a Cossor 210HL. This valve
has a B4 base with 2v heater. With a height of 100mm it has an
amplification factor of 24. This valve is from the late 1920s and
the paper label in use by Cossor at that time may be seen.
||Shown above is a AC/HL triode valve from
Mazda. With the large balloon envelope this again was the earliest
incarnation of this valve. With a B5 base it has a height of
136mm, heater voltage of 4v and amplification factor of 35.
|Shown above is an MH4 from Marconi Osram.
Clearly this is another valve from their "Catkin" range.
The Catkins are further considered here. This triode has a B5 base
with 4v heater. It has an amplification factor of 40 with height of
||Shown above is a Marconi Osram MHD4. This
too has an amplification factor of 40, but the envelope also contains two
diodes. As there would be insufficient pins on a B5 base a B7 base
is utilised with top cap. The valve is not able to handle quite so
much current as the plain MH4 either. Height of 131mm with 4v
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Amplifiers gallery page
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