• 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.

Filament AC or DC?

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Joshua_G

Joshua_G

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Joined 2008
gomeh.com/
Junm said:
So this answers my question posted on other threads here...that using 5Vdc on heaters will not affect tube performance hence prolonged the tube life as well, especially for low power tubes?

I had ask this since i've seen datasheets says 5.7 to 7v ac or dc min and max for tubes. I've tried using 6.3VAC on my Aikido preamp and no hum at all. I had many compact smps 5.1vDC so i want to give them a try.
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It depends on the tube. Some tubes specify heater voltage of 6.3V +/-5%. Best is to have the heater voltage as accurate as possible.
 
D

dtproff

Member
Joined 2008
Please do not forget to use the Constant Current Source or Sink I I like the source better than the sink but that is a different conversation). Without the CCS the filaments get destroyed at startup due to the heater element being cool and at a very low resistance until they heat up.

Also, when you move to standby, drop to 40% on the heater current. this will further lengthen the life of the tube.

Tony
 
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