i have a 10 watt bass amp and a guitar pedal, when i use a 9v battery for the pedal, it runs fine. When i plug in the 9v power chord into the back of the pedal, i get a buzzing/whining sound from my amp, from the current. is the problem that my amp is small and it can't handle this? or is this just a problem that has to be dealt with when using pedals?
what 9v adapter are you using?
Adapters not desined for audio application can cause unwanted noise