A model of this classic is typically included in just about every virtual stompbox collection-just look for the green stompbox. As with amplifiers, a pedal's drive is affected by the interaction/impedance of the physical guitar and its output level. Typically, this interaction is not always possible when using virtual stompboxes, but UA has leveraged its Unison technology for its emulations of the Tube Screamer (overdrive), the RAT (distortion), and the Electro-Harmonix Big Muff (heavy fuzz). What makes these virtual stompboxes unique is that Unison controls the physical input circuitry in its Apollo line of preamps, presenting the correct input impedance to the device(s) plugged in. This means that thehttp://www.usefularts.com