The 3D - Distortion replaces the AH-1 Distortion in my pedal line. The 3D offers three gain / compression settings. It offers volume, tone and gain controls with the addition of a three way mini toggle switch to get you a huge uncompressed drive / distortion down to tight compressed distortion with saturation to spare. Additionally you will find a trim pot on the circuit board that allows you the ability to soften or harden the attack of the gain stage. The pedal is true bypass, uses the same great premium quality passive components chosen for tone - low noise and reliability that are found in all of my pedals. Like the GR8T, the 3D - Distortion features a single gain stage using a low noise selected Op-Amp, and the same circuitry that made the GR8T pedal the success it has become.