240volts and ground hum problems.

[Martin Czech]

> Martin Czech wrote:
> > The mains filter must be grounded to protective earth. It would be useless
> > and dangerous otherwise.
> 
> The Y capacitors (those from the two mains lines to the chassis) are
> there to keep the common-mode high frequency dirt from entering the
> device. Protective Earth is not required to perform this task.
> I don't think it's illegal to have Y caps in a device without PE. If
> this were the case, I'm surrounded by lots of illegal gear =:-)
> 
Yes , this is true.  But these Y capacitors are special devices, you
can't replace them with an ordinary cap.  I have to look that up at home.


I think Chris MacDonald had a good idea to put up a (preliminary) psu schematic.
Since toying with 110 or 240V is dangerous someone on the list should come up
with a recommended schematic for a psu that most people can aggree on.

m.c.