High suspect is the power supply that you are using. Maybe you should describe more on your chain of pedals.
Eg. Guitar-Wah-OD-EQ-Phaser-Delay--NS2-Amp (Power = daisy chain single adaptor to all pedals)
Do list the model names so pple can help more.
Trouble shooting by taking one pedal off the daisy chain power train at a time and using battery.
Recently, one of my jammers using 3 different power supply (2 of which is cheapo newstar non regulated multi voltage type). The hum was incredible, like 1/3 of total output is hum.
