Stand on metal to ground myself instead of a hum eliminator?

[rob aylestone]

This is NOT good. The mixer you have has an internal power supply, so wall wart failure is out of the question. There are two basic paths now. The mixer is faulty. To be honest, with A&H it is unlikely. The test is a simple one. Mixer and headphones =hum with nothing else connected, so take it somewhere else. Your house, but better, somebody elses. If it hums everywhere, it is faulty. It should be silent on its own. If taking it somewhere else produces silence, then without learning how to use the meter, get a proper electrician in. The ground of your basement might have AC volts on it, which it 100% should not. Worst case, it could even be a safety risk. Usual case, is that depending on your home wiring, and I am absolutely not an expert at US wiring codes, you have a bonding issue. Nowadays, certainly in the UK, ground is bonded to the neutral conductor, close to where it enters the building. Other property might not do this and have a ground rod for the safety ground. Losing these, or having a bad connection can let the neutral float up in voltage. It may only be a few Volts, but it can make audio device develop all sorts of issues. Worst case, it creeps up to your mains voltage, with potentially fatal results.

Testing just the mixer and headphones in other outlets should tell you if it is the mixer, or your mains. As death enters the scenario, a test meter would tell you all sorts, but NOT if you dont know how to interpret what it tells you ?

EDIT, your last sentence did not mention guitar, just mixer and headphones. If the mixer without guitar is silent, then take them to a friends. If silent there and not in your basement, then you are into screening your guitar with copper tape in all the cavities. This is also testable with another borrowed or owned guitar.

 

[ecc83]

I would like to just add to Rob's comments. The ZED 10 uses an internal switch mode power supply, i.e. no 60Hz transformer so that initial 60Hz spike HAS to come from an external source. Yes, transferring mixer, cans and guitar to another venue is a very good idea. The more so if the incumbent also has some audio gear. A mains outlet tester would also be very valuable, it can tell you if your mains polarity is correct but most importantly if you have an earth.

Dave.