How to adjust a pitch shifter ?
To avoid "glitch" and adjust correctly the pitch shifter effect, be careful to the Input level, set it to optimum level. At its maximum, it must be close to 0 and sometimes, the red leds can light but not often otherwise there is a risk of input distortion and overload the Analog/Digital converter.
Be careful to the delay function of the Pitch Shifter. If you want a prompt response of the pitch, set the delay to 0ms. The feedback as well.
Be sure to play with a tuned instrument and be careful to set the two Pitch voice parameters to a "in tune" sound.
Finally, avoid to play unorthodox chords. Play simple 2 sounds intervals as fourth or fifth.