I'm not sure if this is the right sub-forum, but I'll try it anyways.
I need to boost a headphone-level signal into a line-level signal so that I can drive a power amp with it. This needs to be done without coloring the sound that comes from the headphones-out and the solution should be about the size of a stomp box. And it should be something that won't cost much
So

, what are my options?