I had a bunch of 741 op amps around and decided to build a preamp myself. I used a inverter amp configuration (quite a simple one) and it worked great. By cranking up the gain by a lot I get a nice heavymetal distortion.
Here is the schematic along with a link to see it running in a free java circuit simulator.
The only problem is that the preamp seems to amplify too an FM radiostation and I can hear some nice music while I play guitar....
At the beginning I thought my guitar was haunted by The Beatles and played on its own, when I hard a kind of a voice I suspected it could be receiving some sort of radio signal..
You don't believe me? Check out this video!