As far as I've ever been able to tell, the Uber isn't really "based on" anything. There's a bit of Mesa Mark DNA in the gain staging (but it doesn't have a pre-gain tonestack, so it's totally different as far as that goes), the tone stack is based on some of Bogner's old Marshall mods but with tweaked component values, and the negative feedback loop design in the power amp was totally original and unlike anything else out there (although supposedly some Diezels use the same design nowadays), using a custom-designed inductor and a fixed depth circuit in really strange ways.
