"Count Floyd" ha scritto nel
messaggio news:BJ4mQCBKg9HM-pn2-3dWudjBJPujT@localhost...
Just changed some tubes in my S-38 and the original 50L6GT was changed
to 30L6GT by my tube supplier. I know that it is the audio output
tube, but listening to it does not seem to make any difference. Is
there a difference? Should I pull the tube and use the 50?
Thanks
--

Firstly the tube that was changed by your supplier should be a 35L6 not 30L6 (to
my knowlegde the 30L6 does not exist).

Secondly the 35L6 and the 50L6 are not exactly the same tube with a different
filament voltage, As a matter of fact the 50L6 is a slightly more powerful tube,
as witnessed by its somewhat higher power dissipation and by the fact that,
despite the higher filament voltage, its filament current is the same as that of
the 35L6 (that is 0.15A). This means that the 50L6 has more cathode emission.

In any case, using a 35L6 instead of a 50L6 causes the filament voltage of all
tubes in the series string to be too high by some 10%. If you have not used your
radio with a 35L6 for a long time, I believe no damage has occurred, but it
would anywy be wise to use the original 50L6.

Regards.

Tony I0JX