Comparing the most brutal Marshall Plexi JTM Black Flag to a JMP

I'm comparing the Marshall JMP sound to the Marshall JTM "Black Flag" sound and we're discussing why the Black Flag is so aggressive and classic sounding. Gear: 1967 Marshall JTM "Black Flag" Model 1987 50" Lead 1970 Marshall JMP Model 1987 50" Lead 1971 Marshall Model 1960B 4x12 2013 Gibson SG CS Aged Close mics: SM57 and 545 Room mic: AKG C414BXLII