What to start first B+ or filaments?

[merlin el mago]

What to starts first B+ or filaments?

TIA
Felipe

 

[famousmockingbird]

Filaments.

 

[merlin el mago]

Thank you. How many time the delay to start B+?

 

[merlin el mago]

Any reliable schematic to delay B+?

 

[jazbo8]

Do a search on the forum, there are literally hundreds of such circuits.

 

[merlin el mago]

That's the question, what's the best one?

 

[famousmockingbird]

The easiest is always an indirectly heated cathode tube rectifier. B+ ramps ups slowly.

 

[merlin el mago]

Thank you. Do you have a link or schematic?

 

[famousmockingbird]

 

[merlin el mago]

Thank you, but lately I use SIC rectifiers for B+.

 

[petertub]

The only reason to delay B+ after power on is if the B+ raises above the
main caps voltage rating before the tubes have begun to draw current.

Besides that there is no need to delay B+.

 

[merlin el mago]

I guess shortened the life of the tube....

 

[nigelwright7557]

I run 100 watt valve amps with SS rectifiers and have never had any problems.
I have no standby switch.

 

[Hearinspace]

Whether the time delay is needed and if so how long it should be depends on the tube and the circuit. Ditto for the delay circuit you choose, though you can add your personal taste as a parameter.

 

[famousmockingbird]

I guess shortened the life of the tube....

From this being discussed in many threads it seems the consensus is for the voltages involved with our typical audio circuits you have nothing to worry about with shortened life.

 

[DF96]

Yes, for normal domestic audio equipment there is no need for power sequencing or 'standby' switches. Done well they do no good; done badly they do harm.

 

[ChrisABC]

filaments, here's a discussion

Proper method to power-up vacuum tubes?

 

[wlowes]

In some cases it depends on the tube. eg 6C33c power tubes. They really benefit from being at full temperature prior to running hard. So in this case I installed a separate power switch to the B+ to allow filaments to heat for 5-10 mins prior to use. Result is very stable tube that many find unreliable. On small signal tubes however, no issue just slamming on the B+ with the filament on a cold tube.

 

[petertub]

filaments, here's a discussion

Proper method to power-up vacuum tubes?

Well, that's one persons opinion, not mine.

As i find no documented case where audio tubes has been damaged by
applying B+ simultaneously with filament i see no reason to delay B+.
On the contrary i have seen and read about problems injected by various
delay things , then i find these devices harmful when misused, and makes no
difference when implemented properly.