Paul, after another round of checking everything including RCA and headphone jack connections I fired it up again with no luck. An RCA nos tube I ordered on the net arrived yesterday, so I stuck it in and the amp works like a champ. After listening awhile, I wanted to try the original tube again. As soon as I turned the amp on the tube started sparking and spitting until I could get it off. I am relieved that my two days of abject failure are over and I can enjoy my well build Crack...Max