You can but the trick is to get the power wire soldered to the center pin and the ground wire soldered to the outer shield. In a wire pair the ribbed or striped wire is usually the negative shield wire. You could just cut off the ends of a standard RCA cable for parts leaving a pigtail for stripping and soldering. It would be best if you put a piece of shrink tube on each of the cable wires before assembly. Once soldered you slip the shrink tubes down over the solder joints, then heat the shrink wrap to seal. In electronics shops they use heat guns but if you are careful you can do it with a match. Black electrical tape could be used but it is not as permanent as shrink tube and could come undone exposing bare wires. You can get shrink tubing, a wire stripper, solder and a solder gun at your local Radio Shack for a few bucks. The wire strippers are really handy to have around anyway. Just to be sure, you can continuity test the wire connections with a volt-ohm meter also available from Radio Shack.
