Otis, I also have a Line 2 and have re-tubed it through Upscale. The back 2 tubes are Amperex 7308s with gold pins. The others are a 'different' version of Sovtek tubes as per Kevin Deal. They don't look like the stock Sovteks that I have seen in the past. These tubes make a very significant improvement in bass definition, soundstage and general musicality. I was so impressed with the tubes sound improvement that I decided not to sell my Line 2. I have never purchased a component from Kevin but I have purchased many tubes from him. He has never questioned me as to where I bought the gear either. This combination is truly a good one to look at for retubing any of the SF Line preamps. Good luck...