1 From the Input block, press and turn the Guitar In-Z knob. This activates it for snapshot control.
2 Set the value however you want per snapshot.
For example, if you have three fuzzes in a row followed by an amp (?!), leave the Guitar In-Z set to a lower impedance for any snapshots where a fuzz is on, and set it to 1M Ohm for any snapshots where all three fuzzes are bypassed.
If you have a single fuzz and would prefer to just turn it on and off with a Stomp mode footswitch, you can also do this:
1 Press and hold the Guitar In-Z knob. Helix jumps to the Controller Assign page for that parameter.
2 Press Knob 6 (Learn Controller) and then press the fuzz’s Stomp switch.
3 Set the Min Value to 1M Ohm and the Max Value to whatever impedance sounds right for that fuzz. Now turning the fuzz on and off will also change the impedance circuit.
– from Digital Igloo on the gear page forum.