I have connected a SMPS (6,3v/2A) to drive the filament of 2 rectifiers,6C4P.
450mA each.
When I connect the power the SMPS´s led starts blinking and nothing more happends.
So I turn of and start again the same happends,the third time the led give lite as it should,and the tubes glow as they should.
What can I do about this?
450mA each.
When I connect the power the SMPS´s led starts blinking and nothing more happends.
So I turn of and start again the same happends,the third time the led give lite as it should,and the tubes glow as they should.
What can I do about this?
The overcurrent protection in the smps is being tripped by the very low resistance of the heater filaments I think. As the filaments heat of a bit
their resistance increases and the smps is able to start. The led flashing is what is called "hiccoughing" If you left the led flashing it would probably start up ok eventually. To prevent it you will need some form of current limiting.
their resistance increases and the smps is able to start. The led flashing is what is called "hiccoughing" If you left the led flashing it would probably start up ok eventually. To prevent it you will need some form of current limiting.
You might be able to use an NTC.
I've done it with a depletion MOSFET and a resistor, too.
Frankly, a better idea would be to use a larger or better SMPS.
I've done it with a depletion MOSFET and a resistor, too.
Frankly, a better idea would be to use a larger or better SMPS.
I got The little bygger smps today,and it starts as it should.
On the downside it is that it cannot be adjusted to higher than 5.7v.
Is this whats called starved filament?
Will it work?
On the downside it is that it cannot be adjusted to higher than 5.7v.
Is this whats called starved filament?
Will it work?
Check with your tube datasheet as your tube are rectifier i don't know if it is allowed or not.
5,7v is sometimes used instead of 6.3v ( for small signal triode) in studio gear ( it is within range allowed at max/min ratings for 6,3v tubes). One brand doing that is Tubetech. It change a bit tube characteristics but the tube live longer.
In tube microphone it is used too ( triode or triode connected pentode).
5,7v is sometimes used instead of 6.3v ( for small signal triode) in studio gear ( it is within range allowed at max/min ratings for 6,3v tubes). One brand doing that is Tubetech. It change a bit tube characteristics but the tube live longer.
In tube microphone it is used too ( triode or triode connected pentode).