By "first pair of each", can somebody explain from which end of the chassis the "first pair" would be. I have a trumpet that sounds really nice with the stock tubes, but I've collected a few RCA black plate 12ax7's and have some Amperex Bugle Boy and Telefunken 12au7's to experiment with. I just don't know which are the first pairs. When I start the unit up, the tubes to the front and rear of the unit light up brightest, which only added to my confusion. The ax's are the same and the au's are the same, so I'm not sure why that would happen.
Help!
