robertkeeley.com Keeley Magnetic Echo... The Mag-Echo pedal simulates tube tape echo sounds by using the PT-2399 and a little bit of modulation. Tape echos have long been regarded as a warm and very guitar friendly form of delay. The Mag-Echo achieves similar results by using a touch of Lo-Fi delay, a filtered echo response, and some modulation. Modulation, or “Wow and Flutter” in the tape world is a slight pitch shift or wavering that occurs as the tape is pulled across the heads. The modulation we use is similar to what we use in our Seafoam Chorus, a slight wavering of pitch on the trails of the repeats. With a simple set of controls for the delay : Time, Regen, and Level and with the “Wow and Flutter” controls : Depth and Rate you can create some very vintage or rather unique tones.