The Astronaut is designed around the Electro Harmonix op amp Big Muff, but has been drastically modified to be more versatile. On low gain it is bright and dynamic while on high gain settings it his thick and compressed like your typical fuzz would be. It also features a blend control not found on the original, great for bass to recover some low end, but also useful on guitar where it can be used to recover some attack on high gain settings. This new version of the Astronaut has a lower noise circuit, a revoiced tone knob, and some other changes here and there. The first harmonic is clipped less, making the sound less boomy, especially on lower tunings. The infamous mid cut of the tone knob has been shifted down to 500hz, which sound more natural to have on bass, it can still be bypassed if you prefer to use an external EQ.