Interestingly enough, I re-installed a circa 1990 Sony Receiver, which was removed from my son's bedroom, he's been out of the house for years, in my main listening room to prep it for sale. I connected it quickly with bare ended wire to some small Klipsch speakers I had at hand. I did not notice that one strand of wire crossed to the other post. Initially, upon the start of an LP I saw a red light on the Sony from across the room but paid no attention to it soon enough and then I lost the left channel. My first thought was the unit was broken and it would cost more money to fix it than I could get from selling it. At any rate, closer inspection revealed the nature of the red notice and of my need to be more careful with the speaker connections.