a hand-built effects pedal based on the EQD humming bird. The StewMac Fan Tremolo circuit has a 3 way character selection in addition to normal modulation It features three selectable tremolo modes, capable of producing everything from smooth, vintage-style pulses to aggressive, distorted textures.

Controls

- Depth (Top Left): Adjusts the intensity of the volume modulation.

- Rate (Top Right): Controls the speed of the tremolo.

- Level (Center): Adjusts the overall output volume.

- Mode Selector: Switches between three different tremolo modes.

Three Demonstrated Sounds

Position 1 – Echo-Like

- Depth: 9 o'clock

- Rate: 3 o'clock

- Level: Maximum

Position 2 – Distortion-Like

- Depth: 3 o'clock

- Rate: 9 o'clock

- Level: Maximum

Position 3 – Fuzz-Like

- Depth: 3 o'clock

- Rate: 3 o'clock

- Level: Maximum

The Science Behind the Sound

Tremolo works by rhythmically varying the amplitude (volume) of an audio signal. At slower speeds, this creates a gentle pulsing effect. At faster speeds, the rapid volume changes introduce additional frequencies, producing metallic, gritty, and sometimes distortion-like textures. The three modes change the character of the modulation, allowing for a wide variety of sounds.

Practical Playing Tip

Try playing sustained chords or letting individual notes ring while adjusting the Rate control. Slow settings create rhythmic movement, while faster settings produce more unusual textures. Experiment with picking dynamics and your guitar's volume knob to discover different sounds.