From KVR Audio:
SoftAmp GT is a virtual emulation of a well known analog guitar amplifier simulator stomp-box. The prototype is a solid state circuit that uses op-amps to saturate and moderate filtering to shape the tone throughout the signal path. The speaker simulation is achieved by a steep low pass filter as well as some middle frequency manipulation to resemble different microphone positions. All controls of the original device are faithfully reproduced in this plug-in in addition to some unique ones. The original stomp-box was criticized for having a symmetrical hard-clipping saturation and there were a lot of attempts to modify the circuit to provide smoother tube-like sound by the community.