You should hear a difference immediately. I use this tube too in my VK-30. (Amperex 7308 white and orange labels).
-Ed
-Ed
I just installed NOS tubes?
I have just replaced my stock 6922's with some NOS Amperex 7308's green label in my BAT VK-30. How soon should it be before I hear changes in sound quality and what should those changes be if any?