Mustang GT + Fender Tone Support has a new home! Click here or go to https://www.fender.com/tone/support to visit our new support home. Related articles Fender® Guitar Amplifier Owner's Manuals (Current) Fender® Guitar Amplifier Owner's Manuals (Archive) How do I update the firmware on a Mustang GT or Rumble digital amplifier? Fender® Keyboard Amplifier Owner's Manuals (Archive)