im starting to convert some old records onto my computer through an amplifier, and without the ground wire i am getting alot of feedback hum.

my question is, exactly what type of wires are used in a groundwire? i went to radio shack and they didnt have them (im assuming because vinyl is a dying breed). They did have the U shaped metal connectors which im pretty sure are the ends of the ground wire. Is ground wire copper wire, speaker wire, etc?

thanks.