Mounting screw terminal capacitors to chassis

[ssmith]

Hi everyone,

Really sorry in advance for the bother.
Having spent months getting all the parts I'm in the process of assembling 2x Mini-Alephs -- see attached picture -- which is my first advanced diy amplifier project.

The caps I'm using are 4x 22,000uf 25v Rifas which have the bolts sticking out of the bottom (I bought these due to ease of attachment). They are bolted to the chassis underneath.

However when running the usual continuity tests with the multimeter to check for shorts anywhere, I see that the casing and the negative terminal of each of the caps are now grounded to the chassis.

Is this normal, or do I have to insulate the capacitor bottom bolt from the chassis, using a rubber washer or something?

a huge thanks in advance for any help.



by the way, the transformer is a plitron sourced in India, there is a softstart, dc filter and bridges from Per-Anders, and the black round things contain hand wound aircore inductors (0.2 ohm resistance, 1mh).

[ssmith]

OK, I did search, but further hunting led me to this thread, which is the same scenario.
So seems I have to isolate the bolt from the chassis...
A bit annoying as I had the base plate drilled and tapped to take the caps, and did not count on the Rifas having the bolt and neg terminal connected. Seem like an odd feature now I think about it.