There's something wrong with one of my power amps. It makes a terrible buzzing noise after it warms up. It isn't the power tubes or the rectifier. It probably isn't the low power tubes. It's probably a bad capacitor. I just hope it isn't the power transformer. It probably isn't. I have a spare everything else from an amp I never repaired that had a bad power transformer. I really need to get around to fixing this. I briefly thought about selling it. I have other amps (in various stages of working), but this is really my dream setup. I think I'd be disappointed. It's a pair of McIntosh MC30 power amps and a McIntosh MX110 preamp/tuner. It's a really fun setup. Time to find my dummy load, variac and multimeter. First things first: what are the voltages at each tube?