All-analog Impedance (Z), Input (I), and Output (O) The Source Audio Zio Front End + Boost is built to, in the company's own words, “make everything sound better." In other words, it's much more than just a simple boost pedal. Featuring an all-analog design, the Zio boasts four distinct preamp circuits to take your tones to another level, whether it's boosting your combo into low breakup or trimming the fat off a thrashing high-gain head! GearNuts guitarists love how intuitive the all-powerful Zio's controls are; output, circuit, tone, and switch are the only functions you'll have to worry about, making it easy to dial in your favorite “always-on” setting. The tone switch simulates how different lengths of cable impact capacitance with self-explanatory bright, medium, and dark settings. A bypass/mute switch controls the dual outputs for easy switching between instruments, plus the ability to add a tuner without introducing it to