Welcome to LQ, Dave.
If your current amplifier has line out, plug it into the line in or mic on your sound card. You will also need audio editor software to capture the input.
Just point your browser at google and search for "linux audio editor". There are several: look them over. You should be able to find one that suits you.
Last edited by bigrigdriver; 07-05-2011 at 12:46 AM.