less hum: switching power supply?

[Jim Patchell]

    Switchers may not be the panacea you are looking for.  I did very low noise
preamps for quite a while, and getting rid of the noise from switchers is a lot
more difficult than getting rid of 60 cycles (or more likely 120 cycles since
generally full wave rectifiers are generally used).  In either case, well
thought out routing and grounding are the only way to keep unwanted power
supply signals out of your signal path.

    Also, if you are going to go the switcher route, you will probably have to
evaluate various switchers to find out which ones are quieter.  Never having
done this myself (I stick with linear myself), I cannot recomend any particular
one.  Jameco (http://www.jameco.com) has a selection of various switchers.
Also, Digikey (http://www.digikey.com) has some.  In both cases, you will
probably want to get a catalog so you can see what they have, and pick one.

    -Jim

chris wrote:

> hello friends on Synth-Diy !
>
>    i'm usually lurking around here, sorry for the sudden surprise entrance.
>    in a quest to totally eliminate the hum in the audio circuits...
>    i've decided that switching power supply is the way to go to get rid of
> the big 60-cycle EMF.
>    could anyone point me in the direction of a small, lightweight,
> onboard-style switching power module: input 120VAC, output +/-15V @ 500mA,
> +5V @ 1000mA.
>
> christo