Mesa Dual Rectifier Rev.F Stock vs. Modded (’US Tone’)

(Jump to A/B cuts at 2:09) Mesa Dual Rectifier, revision F (stock, low serial no.) vs. Mesa Dual Rectifier, revision F (rev.C mod) in a recording setup (Mesa OS Slant cab, USA vintage SM57 Unidyne III) capturing what we call ’the US tone’ (power section pushed, dynamic microphone, close miking). No EQs or any other processing.