If the envelope destination (ENV:DEST) is assigned to MIX, the envelope follower is added to the MIX knob position.  Turn down the ENV knob and the MIX knob should behave like a basic blend/mix control.  

To apply envelope modulation to the wet/dry mix, set the MIX knob to the desired amount for quiet notes (or note decay).  Set ENV:DEST to MIX, then adjust the ENV knob for the desired wet/dry mix on note attacks or loud notes.  

In firmware versions 2.1 and later, the right LED blinks green to indicate that the envelope follower is active and generating a modulation signal.