The "Big Muff Pi" began circulating around 1969. The first version, broadly speaking, is affectionately known as "The Triangle Muff," due to the arrangement of its control knobs. Its slightly smaller body compared to later models gives it the appearance of being the starting point of the Big Muff's history. This is a 1972 model featuring a PCB (printed circuit board) and a power ON/OFF switch. The casing shows signs of use, including scratches, giving it a nice vintage feel. The rubber on the back panel has been neatly removed. It features distinctive minus-top style control knobs. This pedal features four Fairchild FS36999 transistors, one of the silicon transistors that underpin the Triangle Muff's fuzz sound. The tone potentiometer has also been replaced. With its swirling low end and thick distortion sound, this pedal is a must-have that will make a powerful statement. Part replaced: Tone potentiometer Accessories: None *Turning the power switch OFF when not in use will reduce the consumption of the 9V battery. Heartman Vintage Guitars is a specialty store for vintage guitars and basses operated by Ikebe Musical Instruments.