The Input knob provides input trim/boost, for tone and distortion control. The Input range is –18 dB to +18 dB.The Input knob provides a great way to increase or decrease gain with amp models that don't have a separate preamp control. It also provides a way to trim or boost the level of pre-recorded tracks you want to treat with ElevenIt is important to note that the setting of the Input knob is saved and restored with Settings files (presets).