Power Supply Filtering Circuits?

[senko]

I have recently been having trouble with using my own homemade pedals with different power supplies.  At home or with a 9V battery, I get very little power supply noise.  However, taking my pedals to my friends' houses or using crappy wall wart AC Adapters to save some cash, the power supply noise is present.

What I was looking to do was design my circuits so that any power supply plugged in would be immune to any hum or buzz.  My power supply filter design skills are definitely lacking.  I would assume that you would use a low pass filter passive RC combo to remove the high frequency noise.  If this is the way to go, is there a standard circuit to adapt into my designs or is this just something you have to live with or shell out more money for quality AC/DC power supplies

If anyone has any input or circuit snippets/descriptions, I would be very happy to hear from you.

This icon represents my reaction to my pedal's ventures out of the comfy noise-free confines of my basement.   

[deadastronaut]

hi, i haven't tried this myself...but it may help you out ok..

nice and easy/quick to breadboard/build

http://www.beavisaudio.com/projects/Huminator/index.htm