Balance resistors in series filtering

[VacuumVoodoo]

Magnitude of leakage current can vary from cap to cap and over time. If you made balancing resistor current equal to leakage than the balance would be very sensitive to variations i leakage. Making resistor current 5x larger reduces this sensitivity by same factor.

[azatplayer]

Darin, nah mate i think im gonna go separate boards bit like a concorde layout.
That and my glass is square foot, so would need two boards anyways.

I picked up one of Allyns concorde chassis' but dont really need a second one.
Gaz, i did think that 500V caps were more than needed, i do like the idea of this tho and all the little black soldiers look kinda cool

[Gaz]

Yeah, I exclusively use those Nichicon caps. The PW series have the best specs, but I only use those if Mouser has the values I need.

[azatplayer]

Yeah thanks Aleksander, great info!

[gingertube]

Can't find the leakage current for the cap you are using?

This copied from a post I did to another forum.


Capacitors of EQUAL value will share voltage according to their leakage current.
In order to MAKE them share voltage equally you see balancing resistors across each cap. The balancing resistors MUST have a value such that they will conduct 3 to 5 times the expected leakage current.

If you don't know what the leakage current is there is a "Rule of Thumb" to use which is:

Leakage Current = 0.006CV +10uA

C is capacitance , V is the actual voltage on the cap, NOt it's rated working voltage.

This document gives you all the theory - even has a Valve (Tube) Amp Power Supply worked example.
http://www.evoxrifa.fi/electrolytic_cat ... pguide.pdf


Cheers,
Ian

[azatplayer]

I knew i had seen this somewhere, it was on #183 bumble.
He used 470k balance resistors across a whole board of 47uf caps feeding the screens thru the preamp, exactly like im wanting to try. Schweet!
It also had 270K across the main caps.