What brand is the power supply? There's some cheap-and-nasties out there that will deliver 9v at 1A but make a good deal of noise whilst they're doing so.

Overdrives are mostly well below 10 mA draw, so I doubt that's the problem. More likely an inadequate amount of filtering/smoothing on the PSU or a ground loop from daisy-chaining the power to other pedals.

What PSU is it and are you daisy-chaining?

Thanks for the responses.

I am not 'daisy chaining'. this is straight from the guitar into the pedal and then into the amp. PSU is a Cartronic which I bought at the Southdowns store in Centurion.. :-[ This could be the issue right? Would hate to buy a better quality PSU only to find this is not the problem....

The same humm is evident when I switch amps..

rgds

If you mean one of the electronic store like multi-voltage jobbies, that's almost certainly the problem (I usually go off on a rant about them, but I've given up). Try the pedal with a battery and see.

Or You can try a Dataline Noise Filter - Applications: Internal and external power cables

like a this http://www.jantek-elec.com.tw/

Thanks!

Humm is gone when powered by Battery. Too bad some music shop assistants sell the stuff even though they MUST know it just does not do the job!!

As a noob, you end up trusting the salesman!!

Rgds