This ll discrete, MOSFET based circuit provides nearly 30db of unadulterated clean gain boost with a minimum amount of tone coloration. Note that you can also use this as an attenuator by turning the Boost knob counterclockwise away from the noon position. It can also be used as a powerful buffer with an input impedance of around 5M Ohms and an output of around 1K Ohm, best used after your effects chain. This device does not create distortion or overdrive on its own. However, it can be used to drive your favorite amp or pedal into singing distorted sustain. Simple, yet effective. Top notch components and circuit design assure that your signal arrives to its destination in a truly pure state.
When you look at the circuit you can see it's basically a modified SHO.