It has been cutting out, but I didn't think to take a look in the rear to see if the tubes were glowing or not. if I turned it up to 6 & then back down to 4, it would remedy the no sound problem. They're quite loose. I wonder if I'm loosing pin contact? I'm just not getting the bass out of it like I used to. It's more distorted than it used to be, which isn't a bad tone, but it ain't my bag.