The word "ZIO" is an acronym for Impedance (“Z” is the electrical symbol for impedance), Input (“I”), and Output (“O”). The pedal is designed to take a guitar’s high impedance signal, sweeten the tone with any of its four preamp circuits, and output a strong, low impedance signal that won’t be altered by the buffered dry tones of effect pedals further down the signal chain. High fidelity, noise-free Burr-Brown op amps help give ZIO extreme clarity and responsive pick dynamics, while maintaining ideal body and warmth. ZIO has four distinct preamp circuits. JFET offers a completely transparent signal boost with zero coloring or distortion. LOW-CUT reduces “tubby” bottom-end for a tighter sound with added headroom. STUDIO finds inspiration from the time-honored “Pultec Trick,” a studio technique that adds clarity by cutting the “mud frequencies” and adding mid-range articulation. E-PLEX captures the focused and subtle grit of the preamps found in vintage Echoplex Tape Delay units. The ZIO’s TONE toggle offers three different levels of capacitance (or simulated cable length) to brighten or darken the tone.