Reply To: ModFactor: How Many Engines?By yes9310 / April 8, 2009 Home › Forums › Products › Stompboxes › ModFactor: How Many Engines? › Reply To: ModFactor: How Many Engines? April 8, 2009 at 2:06 pm #118482 yes9310Member Excerpt for the manual: There are ten distinct modulation algorithms which we call ?Effects.? Select an Effect by turning the Encoder knob. Only one Effect can be active at a time.