Try moving your amp to a different room and plug it into a different outlet, or try it out at someone elses house. My amps are dead quiet here in my music room, because it's outlets are on a different circuite, but they're a bit noisy in other rooms of my house. At my drummers house, they can get quite noisy. I also get that electrical buzzing from my guitar when not touching any strings, but then it will go away as soon as I touch them. This is usually caused by poor grounding, old wiring, or bad connections.