Vintage 1976-1979 Version 3 Big Muff - 3003 2nd Edition Circuit Board (Same circuit as the Ram's Head V2) - Original BC239 Transistors. *Three Holes in casing from previous external loop mod (no circuit changes from this mod) - Has been modded to change the original ON/OFF switch into a Tone Bypass - pedal turns ‘on’ when lead plugged into the Input jack (as per normal pedal construction).