I found an amp I'm interested in, but I want to know a little more about it, and if it's worth the asking price ($730) It's a '67 Supro Thunderbolt, below are some pictures. From the seller: "1967 Supro S6420 Thunderbolt guitar amp that is 100% original and it works perfectly and it sounds incredible!! It is equipped with a single 15 inch speaker and is still in very nice shape for its age." Anyone care to chime in? What does it sound similar to? 59 bassman? Headroom? Any info or thoughts are appreciated.