Is there any harm in supplying 12v to 9v pedals? I have a couple of EBS pedals and my 9v adapter always induce a hum in them. A 12v computer device supply i have powers them up nicely and the LED also lit up brighter than 9v supply. I send this 12v to a Visual Sound Volume pedal and Fishman Platinum pro EQ and it doesn't seem to have any problem. Is this okay for the long run?