The four effect modes of the 1210 changes the functionality of the intensity knob and allows you to choose between four different effect types all created through the 1210 modulation engine:
This is the Pitch modulation mode also known as ‘Vibrato’. The Intensity knob scales the level of dry signal that is added to the modulated signal. The more dry signal, the less apparent vibrato
In this mode, the intensity knob controls the amount of direct (clean) signal.
The Chorus mode. This is the classic TC chorus known from the SCF pedal. Chorus is essentially pitch modulated signal mixed 50/50 with the original dry signal. The Intensity knob controls the level of pitch modulated signal in this case allowing you to scale how much chorus sound you want.
In this mode, the intensity knob controls the amount of effect signal.
The Flanger mode: A flanger is basically a chorus with a feedback loop creating the distinct ‘canny’ flanger sound. In this mode the Intensity knob controls how much signal is feed back into the flanger, hence how much ‘resonance’ sound you want on your flanger.
In this mode, the intensity knob controls the amount of signal regenerated.
This is a Flanger variation mode, where the signal feedback into the flanger is phase reversed. The reversed phase creates a different coloration to the flanger resonance. The Intensity knob still controls the amount of reversed phase signal feed back into the flanger.
In this mode, the intensity knob controls the amount of inversed signal regenerated.
Additional information can be found in the manual.