Thank you for the guidance, I think they are just the stock tubes, I don't even remember the names. I heard people said the stock tube are intend to be neutral, I'm thinking maybe I can try some tubes which can make it "Tubeier"... TBH, this is my first tube amp, so I don't even know what "Tubey" sound suppose to be, and if I will like it... complete Tube newbie here
Anyway I think there still a lot I need to learn, when I read the thread and people talking about different tubes, I don't even know what are they and where to buy them