I have an old set of speakers that have no inputs or plugs other than an RCA input each. They used to plug into an amp that had what I believe must have been an amplified signal output through RCA jacks... ? Now I want to use these speakers on a new amp, and the amp of course, doesn't have amplified RCA outputs. Can I just take some speaker wires, plug them into my amp, and solder some RCA plugs onto the other end, and plug those into the speakers?