My ancient reassembled stereo, still consisting of components I bought in college over 30 years ago, has some kind of feedback hum. I vaguely remember that this is caused by not grounding my speakers, or something like that. (I don’t really listen to music much, as you might imagine. Mostly talk radio, where a little hum doesn’t matter.) Does anyone know what I’m talking about, and how this might be fixed? I’ve got Martin speakers, I think (the nametag has long since fallen off both) and each of them has four little posts in back, to which I’ve attached speaker wire to two posts apiece and have left the other two naked.
Any ideas? The hum isn’t terrible, but I can hear it when I play soft music.