I accidentally hooked up my 50 watter the other day without plugging the cord running from the speaker cab to the head. I strummed the guitar and tried to turn knobs to figure out the problem of why no sound was coming out of the speakers. I then turn the standby switch off and tried hooking up different guitars and cords. I may have turned the standby on and off 3 or 4 times trying to figure out th problem. I finally figured out that there was no cord running from the head to the cab. When I hooked the cable up and turned the amp back on, the power light started flickering. It eventually became normal after about 5 to 10 seconds of flickering. I do not remember looking at the tubes to much before while the amp was on, but the tubes are glowing blue. The amp also has a constant hiss/buzz even when the volume is at 0. I sure hope I didn't damage something significant, but ???