Strange... Never happened to me... I use my Clean once a week in band practice at high volumes, about 10-11 o'clock, through an 2x12 8 ohm cab. We usually play for 3 hours. Amp is always on, no Eco mode. On thing that have happened a few times though is when im home and using it with the line out for headphone practice. Suddenly some weird clipping happens with hard attack, its not the nutube clipping, its something else... if I then power off and on the amp, its normal again. This has happened a few times.