It's possible to activate the Tuner in the GT-100 by stepping on the 1 and 2 numbered pedals simultaneously. This feature is found in both earlier versions of the GT-100, as well as in version 2.0. In version 2.0, you can now deactivate this feature if desired. Here's how:

1. Press the SYSTEM button.

2. Turn the #4 knob to highlight the PLAY OPTION icon in the left side display.

3. Press the PAGE right button to choose tab #2 in the right side display.

4. Turn knob 8 counterclockwise to choose "OFF" for the NUM 1/2 PEDAL FUNC.

5. Press EXIT when you're finished.  The new setting is saved automatically.