Dear Trelja: The 6CA7 is the American number for the EL34. It might be interesting to note that the 6CA7 pentode was manufactured in a metal shell envelope, similar to the metal 6L6 tube; I am not sure, but I think Sylvania was the maker of this tube. The suppressor grid (grid #3, pin #1) was connected to the shell inside the tube. This was around 1960-63. This tube had to run hot as hell!!