Synthesizer effects pedal for electric guitar with expression pedal input. The Synth-1 allows you to create fuzzed-out synth waves! Use the Filter and Blend controls to mix your guitar with the fuzz from the synth. Go from churning slow-gear reverse swells to sounding like a light saber. The Keeley Synth-1 is a guitar-triggered, single-note wave generator. You control the tone of the wave with the Filter Control. The lead-in time or swell of the note is controlled with the Attack knob. Then use the Blend control to remove the natural tone from your guitar as you slide through synth-sounding fuzz waves. Use an expression pedal to control the Filter, and now you have Wah-Wah-like control of the Synth-1.