• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

best long life for my tube


2003-09-16 7:04 pm

In my amp i use 6vac -5% for the heaters and i was sure
in my mind to get the best long life for my tube but now
i read some thread saying -5% is the strict minimum and
now i m not sure .

my tubes are indirect heated triode:

6SN7 5ma ~25% of pa max.

6AS7 70ma ~60% of pa max.

i would like to get your opinions on my low 6vac and % of
pa max. for my tubes

hi Sch3mat1c

Pffbt. 10,000 hours minimum.

.......it s more or less than normal 6.3 vac tube life

You do realize that you're practically running more heater than plate dissipation in the 'AS7? What a waste...

.......i don t realize but you r right :) but it s the only way
i found to get zout=50ohm with just 6db feedback
and the 6AS7 is not easy to drive to :) but 6AS7 is
great tube to do special thing impossible with other