The Stack in a Jack™ does not change the tone of your instrument, This allows the full frequency of your instrument to pass through, this is why it sounds more like amp distortion. It is the Warmest, Smoothest distortion you have ever heard. Between the Distortion, Tone and Master you can get any amp to come Alive! "It really acts as one of my guitar amps, the distortion is fully controllable by your guitar, Make the Cleanest guitar Growl......Lee