Ziggy is a low to medium gain overdrive that is designed to respond like a tube amp. Unlike most overdrives it does not feature a "mojo" opamp but cascaded discrete (MOSFET) gain stages that give ultra touch sensitivity.
Gain knob acts as a voicing control adding more bass as you turn clockwise, choosing from jangly and sparkling clean to thick crunch of a tube rectified amp . Tone knob behaves as a presence control adding bite to your tone.