AF-9 Auto Filter
The Maxon AF-9 Auto Filter is a professional-grade analog envelope filter designed to deliver the classic, watery wah effects made famous by the legendary Mu-Tron III. Originally released in 1981, this Japanese-made pedal utilizes specialized opto-coupler circuitry rather than standard VCAs to achieve a warm, organic, and vowel-like filtering that responds dynamically to a player's pick attack. The unit offers extensive tone-shaping capabilities through its intuitive interface. It features two sliders for Sensitivity (Threshold) and Peak (Resonance), along with four toggle switches to customize the sweep. Users can select between three filter types—Low Pass, Band Pass, and High Pass—and choose between two frequency ranges (Low and High). Additionally, the Drive switch allows for both upward and downward filter sweeps. Housed in a durable metal enclosure with true bypass switching, the AF-9 is highly regarded for its ability to provide expressive, human-like vocal textures for both guitar and bass.
