• 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.

voltage doubler switching noise

Hello. I am using this for my preamp heater circuit:

psb.png


I also connect that the output to an LM555 timer that activates a relay and all sort of jazz.
the thing is that i get some mishaviours because of this turn on noise:

1.jpeg


if I switch it off and turn on again, looks like this, and everything works flawlessly:

2.jpeg


any idea on how to reduce that noise?

is this because of the voltage doubler?
the diodes inside the BR310?
may be transformer inrush current?

THANK YOU!
 
The output from the regulator will pass all the incoming ripple until the regulators specified minimum Vin/Vout differential is reached. That will be around 2 to 3 volts at high current. 10,000uF on the output of a reg is not recommended. Try reducing that to around 10uF.
 
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I dont think Im getting you.
If I set the RC filter to get 6.3V when the heater has kicked in.. I would have >6.5V when the relay hasnt kicked in yet..
Thats why I said I had to add an extra resistor for that lapse of time.. to keep the heater voltage at 6.3v during warm up.
Unless having it in 6.5V for one minute isn't harmful?
 
Hello. I wanted to report back on this issue I had.
I finally replaced the regulator with a couple of wirewound resistors. Much less heat (the LM338 needs Vin-Vout > 3V) and the transformer load is lower than before.

But the problem I had was fixed by increasing the capacitor in trigger section of the LM555 from 0.22uF to 10uF.
May be an 1uF capacitor would have been enough though.

1744031919527.png


Thanks for all the suggestions.
Cheers.