• 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.

CC Filament Power supply performance.

Hi, in Sakuma tube amps, there is a lot of examples of simples diodes + CLC or CRCRC (bigs C) CC filaments supply. Even in DHT tubes. Is this CC filament supply type a good performer?


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Rod Coleman

Paid Member
2004-07-25 6:55 pm
> Aren't most indirectly heated tubes rated for +/- 10% heater voltage and filament tubes rated +/- 5%?

Yes, 5% in some cases, 10% in others. But such a wide range simply reflects the reality of mains supplies: the valves were being sold for use in mains-operated consumer equipment.

It does not mean that the lifetime is the same, anywhere from -10% to +10%.

This snippet from the Philips Technical review [1956 ed.] gives some guidance, and shows the benefit of never going above the nominal voltage.