i built a decent 200 watt amp for just music and whatnot. however, when i hook it up to an audio source that is also plugged into the wall, it creates a buzzing sound and blows the fuses. For example, if i have the amp plugged into my laptop for music it works great, but once i plug my laptop into the wall to charge, the fuses blow... so any ideas what it could be or how i could fix this??