On Mar 24, 9:31*am, Henryk Birecki wrote:
Here is a reply I sent to JJ's note on March 9 2007. As an added bonus
a question (good for EE job interview): Why does wrapping DC power
cord around ferrite core work to suppress noise? The supply and return
currents should cancel itself.
[snip]

Henryk Birecki


Not sure I'd pass an EE job interview, but inductive coupling of the
switched current can produce in-phase noise on both input leads. The
power supply circuit inside the Zaon may have issue with how it
handles RF grounding that makes this more likely.

At least in my case wrapping both leads a few times though the ferrite
choke worked. If it does not then slitting each lead and doing this
separately should fix things. Failing that use a full on filter like
Henryk describes.

BTW a nice power supply cable for the Zaon is aviable from Digikey see

http://www.digikey.com/scripts/dksea...196-ND&x=0&y=0

Darryl