My roommate and i both have ampeg svt II's and we just retubed his last night so he would have it up and running for his show tonight. He took mine with him as a backup, and set it next to his cab while he ran his. But he had mine turned on in standby the entire set, and he didnt plug it into a cab the entire time he had it on. I know its bad to run tube amps, or any amp for that matter, when its not hooked up to a cab or a dummy load. Could this have ruined my amp? Or the tubes? I plan on firing it up later tonight to see if it still works. Im really terrified right now seing as neither he nor i have the money to fix it if its fried.