Re: headphone tube amp concern


"Robert Baer" <robertbaer@xxxxxxxxxxxxx> wrote in message
news:dp9ch.5581$sf5.5549@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
John Cash wrote:

I would like to build a small tube amplifier for my headphone. It is
working in classic class-A with a penthode 3E5/3S4 working at about 67V
and a small output transformer 8000 ohms/32 ohms. The cathode of these
babies is also the heater with a low 1.5V heating voltage. Not top of the
line tube but, well, they sounds ok for me.

The prototype I built is working nice but I am concerned about the
possibility of a tube giving up abruptly while listening to music.

Is this a possiblity for a tube to cut off abruptly when dying, thus
sending a loud "pop" in the headphone. Would not be good and probably
dangerous for listener's ears.

I don't know if tubes can behave that way or this cannot happen because
of unknown reason for me.

Anyone got experience in this matter?

John


Tubes do not have that problem; usually the gain slowly decreases due to
lower filament emission long before the filament would even think of
opening (and i have never in 50+ years heard of a tube filament opening if
powered properly).

If you never experienced that problem then... I go on with my project!

Thanks!


.

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