I'm a real novice with tube amplification!
I have just acquired a ST-70 from Ebay. Unfortunately I didn't have the chance to enjoy it for very long. Today I received a new preamplifier, so I decided to try it with my amp. I connected the amp to the speaker and preamp to amp, turned the power on, and started to play music. But no sound was coming. So I rotated the selector switch, still no sound. What I made is a bad idea. I disconnected the output of the preamp and heard a huge thump through the speakers. I realized it's not a good thing to play with the preamp output while the amp is still powered, so I turned off the amp, and connected it to another preamp output. I then turned on the amplifier and a small flash occurred at the rectifier tube, and the amplifier went dead. Nothing is working anymore.
Does anyone have a clue what happened? I hope I did not damage my dynaco too much!
Thanks very much for any help.