Hi - not looked myself yet as Im not at my mums, but shew runs a dance thing, and uses a PA/music system. She has had no problems for ages, but now both her micrphones just cause squeel when switched on (have on/off switches). They both have dedicated cables so not likely to be that - and there both Low Z.
They have a third mic which is duel impedance - again with its own cable. When on Low Z she gets the same squeel. When switched to High Z all is fine.
So - what has happened that now causes all low Z micrphones to just produce squeel but high Z micrphones work OK.
Comments
That's assuming that none of the other obvious factors have changed like speaker position.
Also had something wrong with a speaker cable, intermittent loss. I'd already made up new cables. Mum was shocked, I'd used good quality summer 2.5mm core stuff. Weighs a tonne compared to the crappy string she was using (supplied with pa), but sound is so much better.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein