some of those boxes act as pre-amps

Yeah, but this box is not one of those. My guess is that chocorua has a preamp anyway, since goddessfarmer says he has playback capability.

I have one of this box, branded Creative Labs but clearly the same box. It really is just a way to have line in/out on your computer if your computer happens not to already have those. goddessfarmer, I'm happy to lend it to you if you'd like.