Penumbra

Aion FX from Des Moines, IA has helped guitarists build studio-quality effects since 2011. They specialize in ZVEX circuits that command premium prices as originals.

The Penumbra is inspired by the ZVEX Woolly Mammoth and Mastotron, taking elements from each with modifications for better usability. The Woolly Mammoth is a full-frequency silicon fuzz featuring controls for fuzz level, EQ, pinch (pulse width), and output volume. The Aion version adds a transformer-based pickup simulator and Subs toggle for enhanced versatility.

Originally designed for bass but adopted by guitarists seeking extreme fuzz tones, the Woolly Mammoth delivers thick, wall-of-sound saturation. The Pinch control creates unique gated textures impossible with conventional fuzz circuits. The Aion adaptation improves flexibility while maintaining the original's gnarly character.