I've been playing through a borrowed 60's era Ampeg, and I'm considering purchasing it. I've done a bit of searching around for info on vintage Ampegs, and I found a few sites, but I can't find my model. It's a flip top head over a 2X15 cab. The sound is thunderous. Unfortunately, I haven't looked for a model or serial number on it. The owner plays guitar in my band and the amp stays at his place. When I'm there, I'm too occupied with playing to pay any attention to the details of the amp. Anybody know a site with good pics of old Ampeg's? Also, what should I expect to pay for this amp? I've been given a starting offer for purchase at $400. I'm pretty sure that I'll be ripping the poor guy off, but that's what he paid for it, so he's willing to sell for no profit. Any suggestions?