AETHERPHON, global theremin family

Sorry, I should have specified.
Don't need battery or portability.
Just need to practice. I have no $$ really to buy anything at the  
moment.

I have a stereo system. I can play the theremin thru it? I was afraid  
I'd blow it out or something.
It's a Kenwood stereo receiver and the speakers are bookshelf (sony)
I guess what you told me about the computer speakers applies here?-Go  
to Radio shack and get the appropriate jack(s) and so forth?

Thanks for your straightforward and very helpful answer!
This is the third group where I've posted the same query and this  
answer is just what I needed.
Jul