before dropping some dough on a custom autosound unit for my '56 i thought i may see if i can get the original 12 volt radio to work. the p.o. had clipped two of the three wires on the back top left side of the unit. the wire that is still intact goes to the bulb in the bottom on the unit. of the two clipped wires one is both a heavier guage and copper. would one of those wires be powered from the ignition switch and the other a ground? i'm assuming that the inlet hole in the center of the bottom is for the speaker? if so can a mono speaker from radio shack be used; i have an extra one that has a + and - terminal on it. i realize the am selections are somewhat limited but even talk radio would be better than my own singing. thanx, dave b.