Signal polarity – often referred to as Phase – changes the pickups relationship to the sound coming from the amplifier. Inverting Phase can reduce feedback. With low volume playing, it can improve the intensity of low frequencies you hear. Try flipping phase while playing and leave it in a position which sounds or feels most natural when playing.
With the pedal powered on, press the footswitch for 3 seconds and the signal polarity will be inverted. Repeat to return to normal polarity. You can play and listen while you make this change.
