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PAS-3 filament voltage doubler capacitance

Posted by sbalfour@att.net on October 10, 2013 at 17:48:48:
I'm refreshing most of the components in my stock PAS-3 (except that the
filament selenium rectifier has been replaced with a pair of diodes),
including the two 2000uf 18V caps in the filament voltage doubler. I've
searched the web to see what people do with these, and I saw everything
from two 1800uf caps to a total of 100,000uf (he didn't say what the two
caps actually were). 4000uf is actually substantial capacitance for a
circuit not expected to carry substantial load, or be subjected to large
transients. Increasing capacitance here is just logarithmically reducing
the ripple. I'd think 1/10 the capacitance (2x220uf say) would be
minimally adequate and probably not have a detectable impact on
performance.

I can find a pair of 47,000uf (or 56,000uf) 35v caps that'll fit in the
space to make up ~100,000uf, but the cost is unseemly: $42. If I were
going to spend money on capacitance, it wouldn't be here. A better answer
to reducing ripple here than humungous capacitance is a better circuit.
I can design an 8-component voltage doubler with substantially reduced
ripple using just two 220uf caps.

Most designs I've seen up the doubler caps to between 2200uf and 4700uf
with the claim of tighter bass and etc. I doubt it, because these
components are not in the signal path. Still capacitance in this range
is cheap and readily available (I have a pair of 35v 3900uf caps in my
junk box). What's really needed here? (Skip the lecture about a regulated
PS - I know, I know).
Stuart