Re: CD changer
I think you will need over 11 dcv to be able to turn it on. Yo can try it.
If you have one of those 110ac to 12vdc chargers or transformers and connect the leads from the tip, you will need some alligator clips, pins or extra firm young hands to keep the connection while you do that. Radio shack sells those transformers, tips and maybe leads to do that. An old car battery will work too.
8 tipple a or double a batteries all connected together will do the trick too, just hard and time consuming to connect them.
Good luck and let us know how it went