G-amp Phat is a virtual guitar amplifier based around the distortion model used in G-amp Lite. The distortion created by the simulation can create mixed order harmonics (both odd and even), a varying duty cycle, and becomes more harmonically rich with increased gain, as you would expect in a real valve guitar amplifier.

G-amp Phat has two pre-amplifier stages that can be used in parallel or in series. When used in parallel G-amp Phat can create stereo guitar parts from mono sources.