I could probably have answered this question with no difficulty some 55 years ago. I used to play in a skiffle group and we had a regular Sturday night gig in a local youth club.
This involved carrying a huge radiogram (if you can remember them), with a 12-inch speaker, down the street to the club. The lead guitar (for the musically challenged this meant the one that played louder than the rest) was plugged into a socket using bare wires and matches. Ingenious use of sellotape (Scotch tape for US Mudcatters) allowed the mike to be linked into this. The mike itself came from a WWII tank and was on a stand that during the rest of the week supported a budgie's cage. Later two more speakers were added to the setup - one didn't even have a case! This was real hi-fi!

We did have the occasional shower of sparks and sometimes all the lights went out, which was fun but nobody was actually killed.

Nowadays everything is so much more complicated - or illegal!

Eddie