Russian 6C33C and 6C18P
In 1976 a Mig 25 fighter jet landed in Hokkaido in Japan, it was flown
by a soviet military pilot that wanted to defect to the west. This was a
real field day for western miltary people as not so much was known
about the MIG 25 and the plane was completely dismantled.
Two things startled the military analysts in the west, the first was
that the plane was built using a lot of high tension steel, it was
earlier thought that the MIG 25 was built in Titanium to withstand the
heat that is generated by flying at mach 3 that the plane was capable
of, that it was built in steel made it heavy so the performance was
actually less than expected.
The second thing that surprised people in the west was that electronic
tubes was used in some parts of the radio equipment. After a while it
was understood that the tubes where used so the plane should be able to
withstand EMP. An EMP, (Electro Magnetic Pulse) is generated by the
detonation of a large nuclear bomb in the atmosphere, the electric field
so generated destroys most solid state electronics and EMP is thought
to be used as a possible electronic warfare measure.
In the power supply of the main radio unit of the MIG 25 a previously
unknown triode tube was used, the Soviet military designation was 6C33C
and it was a voltage regulator triode. The data of this tube was much
better than anything made before in the west and SanEi of Japan imported
some 6C33C tubes for audio application in 1997, renaming them EC33C for
the Japanese consumer. Mr. Dakesue in Japan was the first person to
design a 6C33C-B OTL power amplifier circuits in 1977.
The main characteristics of the 6C33C is that it has very high
transconductance, high current capability and low internal resistance
and also as the tubes where intended for use in miltary aircraft they
are mechanically very robust. The nearest western equivalent is 6336 but
data of 6C33C is better.
6C18P younger sister of 6C33C
