I have a mackie mix8 mixer, which comes with a cheap power supply that generates a loud hum (at least I think so -- I don't have a different power supply at the moment to verify)
I noticed that if I connect the mixer to the ground (for example by touching the outside ring of microphone out with one hand, and kitchen sink with other hand), the hum goes away.
Power connection on the mixer is a standard barrel plug with 2 contacts, so apparently it was not designed to be grounded.
My question is, should I ground the mixer, and is it safe to do so?
Or should I just get a better power supply?
I'm not connecting the output to a computer or any other device, it goes into a digital recorder which is battery-powered. Input is a microphone. So I don't think this is a grounding loop issue. The hum is audible whether the microphone is connected or not.