In the words of JHS Pedals:

We are proud to release the Paul Gilbert signature distortion “PG-14! This is a new and unique distortion pedal specifically designed to Paul’s specifications. At the heart of the circuit is a FET based distortion engine that emulates the touch, feel, and the response of a pushed tube amplifier.

This circuitry allows the player to have the dynamics and tone of loud stadium level amplifier at low/moderate volume levels.