Yes there's an app. Once you fire it up you can access the patch settings and levels. It sounds strange that it should be crackling and cutting out, though. Check there's no debris in the headphone jack. It might be damaged, because it definitely shouldn't do that, volume issues aside. Also, I'm pretty sure the display function you describe is normal until you change something in the settings. After a while it'll revert back to the circular pattern presumably to save battery.