To create a Slow Gear effect, take the Volume block and attach an ADSR controller to the VOLUME knob. Configure the ADSR MODE for SUST and put RETRIG ON. Set the DECAY and RELEASE to zero, and the LEVEL parameter to the max. (SUSTAIN doesn't really matter.) Adjust the THRSHLD to somewhere around -50 dB where it will trigger when you play a note (and not stay open with background noise).
The ADSR's ATTACK control now determines the speed at which the input signal ramps to full volume.