TC-Helicon Harmony GXT Product Manual page 8

Quick Start
Step 5:
Set the Input Knob fully left then set the Guitar, FX and
Harmony knobs to the 12 O'Clock position.
Inst
Input
Tone
Auto
Preset
3
#
8
Guitar FX Harmony
Hall Higher
Room High
E h L
Step 6:
Connect Harmony-G XT's power adapter to main
power and to the Power input on Harmony-G XT.There
is no power switch so plugging it in automatically turns
it on.