(Jump to A, B cuts at 2:08) 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, MJE Hulk 990 ) capturing what we call the German tone (master volume rolled back, condenser microphone, short distance miking). No EQs or any other processing.