AF9 Auto Filter

The Maxon AF9 Auto Filter is an analog envelope filter pedal designed to deliver classic auto-wah and sweeping filter effects. Utilizing opto-coupler circuitry, the AF9 produces filter tones reminiscent of vintage analog filter pedals. The Threshold and Peak sliders enable adjustment of filter sensitivity and effect intensity, while Range and Drive switches control both the sweep range and its direction. The unit features three selectable filter types—Low Pass, Band Pass, and Hi Pass—covering a frequency spectrum from 100 Hz to 4 kHz, making it adaptable to a wide array of instruments and signal sources. **Key Features:** - Analog envelope filter pedal with opto-coupler circuitry - Three filter modes: Low Pass, Band Pass, and Hi Pass - Threshold and Peak sliders for effect depth and sensitivity control - Range and Drive switches for adjusting sweep range and direction - Frequency response from 100 Hz to 4 kHz - Compatible with various instruments and input signals