600V Capacitor

[Mick Bailey]

The Ceriatone kits have some decent looking caps. I've worked on a few of these amps just sorting out build problems, but not come across any issues with component quality. I don't know who makes the caps, though.

[J M Fahey]

Personally I would *measure* them.

My simple/basic procedure I have used for decades is to:

* get a high voltage source, say 800-1000 VDC or more.
Say a voltage doubler fed from a regular 300 something PT, or a single HV diode (we are not worried by ripple here} connected end to end, half wave feeding 2 or 3 400-450V caps in series, as needed and with proper ballast resistors.
Again, we are not testing *these*, it's just a high voltage source built out of common junk/spares box parts we all have.

*BE VERY CAREFUL, THIS HOLDS DEADLY VOLTAGES*

*Connect said high voltage to capacitor under test, through a 50-100K resistor, made up of 2 or 3 in series. We need to add their voltage ratings, a single one will not do.

Also include a high voltage diode in series, or 3 1N4007 in series, NO balancing resistors in parallel with them, the idea being that the power supply does not empty the capacitor under test when unplugged.

The idea is to feed a couple mA into test capacitor, 5mA tops.

Capacitor voltage will rise (it's an RC network after all) somewhat faster at first, then slower and slower.

When it stabilizes, it means *internal* losses are equal to current being injected.

Unplug supply, test capacitor voltage will drop, quickly at first, then stabilize, which means internal losses are negligible

THAT is my new peak/surge/maximum voltage rating, which I can trust.

My new *working* voltage is 80% of that.

Slow clumsy method but has served me faithfully.

Get ready a couple plastic or glass sticks with metal probes (even if filed head nails) attached joined by a proper wire and a 50-100k resistor to discharge tested capacitor

I did not include a "permanent" discharge one because I depend on capacitor's _own_ losses as indicators, a permanent one will discharge it down to 0V and tell us nothing