Ok so Im leaning towards getting a SF Bandmaster, scoping them out, learning about them. So I stumble on this '68 circuit delima.. read under comments :http://www.ampwares.com/amp.asp?id=18 So apparently the early 68 has the blackface AB763 cicuit, and later 68's have the AC568. What I want to know is, is there any cosmetic difference so I will know which to aviod? I know the 68-69 have the drip-edge, black lines, but does the AC568 cicuited amps have the same look? Id really like to get the AB763.