I just bought an acoustic/electric guitar, and I'm wanting to connect it to my computer for recording. If I connect the guitar directly to the mic input of the soundcard, the sound is really weak. I've read that I should use some kind of preamp inline. I bought a little Behringer AT108 practice amp, so can I just hook the headphone-out jack of the amp to the line-in jack on the soundcard? What's the difference between a pre-amp and an amp?