I've started with shunts only and don't hear it. I am very aware of the volume levels. Add a cab and it's still not audible. As soon as I add an amp block, even with all volumes as low as can go but still being able to hear the signal, it's there.Do you get this noise when you run through the AX8 in global bypass? If no, then have you deconstructed your presets from scratch, making sure that with every block that is added, you are keeping the volume block's level somewhere near that of the global bypass state?