input impedance

Input impedance is the resistance a pedal or amp presents to the signal coming from a guitar's pickups¹. It matters most with magnetic and passive piezo pickups, where high-level input impedance is especially important in the interaction¹. A high input impedance preserves signal quality, timbre, and expressiveness², while a low input impedance, as in a classic Fuzz Face, shapes the character of high gain fuzz³. Some pedals offer variable input impedance, ranging from 10 megaohms for a brilliant sound down to 10 kilohms for classic "tone suck," allowing tone-sculpting with or without the effect engaged⁴⁵.