[sdiy] wall warts--wishful thinking

[harrybissell]

everyone complains about switchers... but try getting rid of 60Hz AC induced
hum in high gain audio paths... it ain't any easier

The weapons are different... Mu-metal shields, lots of steel (iron better)...
and distance.   Switchers need ferrrite beads, pi filters, and sheilds (at
least
they can be copper or aluminum, but they need to have no cracks in them :^)

I ran for years with an old Lambda +/-12V supply (switcher) and never had a
problem
that I could identify as power supply related (unless I caused it by bad design
in the
first place)

H^) harry

Scott Stites wrote:

> Don't know if this would even apply (looks to be built more for high freq
> DC-DC convertors), but the latest BGMicro flyer had this item:
>
> "FLTR100V20 filter module.  Optimized for use with high frequency dc to dc
> power modules.  This module is designed to reduce the conducted common-mode
> and differential-mode noise on input or output lines of high frequency
> switching power supplies.  The module has a maximum current rating of 20A.
> Measures 2"x1-9/16".
>
> Made by Lucent.  BGMicro P/N PWR1202  $1.99 each.
>
> ----- Original Message -----
> From: "John Blacet" <blacet at blacet.com>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Tuesday, August 16, 2005 3:15 PM
> Subject: Re: [sdiy] wall warts--wishful thinking
>
> > I did some very basic external filtering work with a small switcher and
> > got nowhere! Obviously, this not trivial.
> >
> > If anyone comes up with a decent filter or some technical info of
> > interest, let us know.
> >
> > It would be great to get rid of heavy transformers and get more
> > efficient energy wise.
> >
> > --
> > Regards,
> > John Blacet
> >
> > Blacet Research
> > http://www.blacet.com
> >