• 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.

6V6 line preamp

Normally one would look first at the changes that usually caused the issue. The tubes were OK and haven’t been changed.

However, I think I pointed out in post #4830 quite some points where things can be made as they should be. It seems the changes uncovered some existing imperfections. It is hard(er) to solve issues with introduction of new variables. First basic rules and troubleshooting.

No offence but it would be a miracle if the device was dead silent. Dead silent = as in the semi world so ears before the woofer and no hum.
 
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Miracles happen apparently. Because as you can read in earlier posts he says it was dead silent. So if you pull out tubes and insert them...that might take em over a threshhold. But that is just guessing....ofcourse. I had tungsol 6v6...after a while of use...white flakes were loose inside the tube....pulling them out and laying them flat may have caused something...Anyway... All is well that ends well. I'm sure he'll get it dead silent again.
 
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Miracles happen apparently. Because as you can read in earlier posts he says it was dead silent. So if you pull out tubes and insert them...that might take em over a threshhold. But that is just guessing....ofcourse. I had tungsol 6v6...after a while of use...white flakes were loose inside the tube....pulling them out and laying them flat may have caused something...Anyway... All is well that ends well. I'm sure he'll get it dead silent again.
ok...ok....maybe I was exaggerating a bit....but 15db version was enaught quiet...only little buzz if I put my ears near drivers....
now it's annoying from listening chair...

BR,
Goran
 
This one is a working design in a G3X. No failures in two years since installed. Not a regulator. Fixed voltage reference capacitance multiplier ripple filter. You could also add a 220R stopper next to the Mosfet's gate pin for good measure.

Mult PSU 6V6 line final.png


IMG-Mult PSU final.jpg