07-31-2017, 07:40 PM
Hi and welcome,
I would go ahead and use the 450v guys. I think most are rated @ 475v peak. Tack it in and measure the dc voltage across it. What you'll see is the voltage will creep up and up till the power supply has some load across it. Then it will drift downward till it stabilizes around 300vdc.The real issue is that the rectifier filament ( directly heated) heats much quicker than all of the other tubes. Till the others heat there cathodes there is very little current being drawn from the HV. This causes the HV to surgre upwards till all the tubes are heated and drawing current.
I would go ahead and use the 450v guys. I think most are rated @ 475v peak. Tack it in and measure the dc voltage across it. What you'll see is the voltage will creep up and up till the power supply has some load across it. Then it will drift downward till it stabilizes around 300vdc.The real issue is that the rectifier filament ( directly heated) heats much quicker than all of the other tubes. Till the others heat there cathodes there is very little current being drawn from the HV. This causes the HV to surgre upwards till all the tubes are heated and drawing current.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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