In article ,
zappa wrote:
I found to be spending quite a lot of money in throw away batteries using my
Sony ICF-SW7600GR portable receiver. Thus I bought a filtered (stabilized?)
power adaptor (a generic one), it works well within many frequencies but on
some of them (always AM) there's background noise and it's impossible to
listen to LW, as it makes too much noise there.

I assume it has something to do with the mains, so my question is can I do
something to filter, even more, the power cord that goes into the receiver?

Try hooking the receiver chassis up to an earth ground. If it's
just a two pin plug on the wall wart, the receiver is floating, ie.
connected via stray capacitance to all the crud coming in over the
power line.

The battery clip on the ground end, or the outside of an earphone or
antenna jack are places to try. (I don't have that radio, anybody
have a service manual and can make a better suggestion?).

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)