Keeley MAG-ECHO Magnetic Echo DelayMagnetic Echo Modulated Tape Echo Keeley Magnetic Echo The Mag Echo pedal simulates tube tape echo sounds by using the delay circuit 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 slightly filtered echo response to keep things warm, and some modulation. Modulation, or Wow and Flutter in the tape world is a