It's a failing of the programming. You need to have the TIME/DIV set to Zero and the DIV fader set to 1/1 for the tap tempo to work. This info is nowhere in the docs that I can find. and frankly a pain in the butt for those of us who play and mix from the stage. You would think that the tap tempo would override the delay time setting...considering the foot switch will control the tempo...but no, we have to hit 85 buttons and sliders to get a good timed delay effect to work. Ugh.