Hi there, I have never had a problem with my reissue Marshall in over 1 year of gigging with it but about a week ago I was trying out a new overdrive pedal when all of a sudden I heard a drop in volume followed by a burning smell. I quickly looked through the back grille and saw a tube really glowing colpletely orange. Switched it off immediately and had it checked with my tech. He found nothing and since then I have gigged with it twice without a hitch, tubes were replaced with Svetlana winged C two months ago. Does anyone know what may have caused this? Its these little things that keep you up at night... Thanks guys.