The LEAST expensive way to get it running is to strip an inch or so off the ends of some ordinary lamp cord wire. Twist one wire and stick it in the RCA of the pre-amp output. Wrap the other around the outside of the RCA. Do the same for the other channel. Connect the other end to each speaker.
It won't play loud but it will play. It won't be permanent, will probably need a rubber band to hold onto the RCA, but it will get the job done. And if you have enough wire laying around it will cost you nothing.
You could even go just like this direct from the CD player. But the pre-amp will be better. It for sure has volume, and will have a lot better output stage that might even be good enough to sound fairly decent.
It won't play loud but it will play. It won't be permanent, will probably need a rubber band to hold onto the RCA, but it will get the job done. And if you have enough wire laying around it will cost you nothing.
You could even go just like this direct from the CD player. But the pre-amp will be better. It for sure has volume, and will have a lot better output stage that might even be good enough to sound fairly decent.