I have an m-audio firewire solo and an audigy 2 zs PCMCIA for my laptop. Both give off a buzzing which varies depending on system activity (e.g moving the mouse causes it to change) when the laptop is connected to the mains (output through any form of amplified system, PA, guitar amp etc.. ). It is unfeasible to perform a whole set on battery, so is there any equipment you could recommend that would filter out or eliminate this buzz? Perhaps even an amplifier / speaker system (suitable for stage use) which would work well with a laptop (being used as a virtual instrument host).

I've tried through 2 different PA systems and 3 guitar amps, case is always the same...system buzz while connected to the mains. I've tried using a mixer to filter out the noise but as my soundcard/interface doesnt have a GND to connect to the GND on mixer I guess thats useless hehe...

thanks for reading!