just make sure it should and will sound different and it will. if you do contrary, it won't.
there certainly things that will sound different believe it or not as well.
12-09-14: Czarivey
Ain't that the truth!
To think of all the money I wasted about 8 years ago buying several pairs of NOS early 1960s white label Amperex PQ 6922 and 7308 tubes. Not to mention Siemens early 1960s all grey plate CCa and E188CC tubes. It was all in my head the differences that I heard from the stock 6922 Sovtek tubes that came with the preamp. Funny thing though, I still remember the preamp sounding like a solid state preamp with the stock Sovtek tubes installed.
Measurable test results showing the differences in perceived sound of vintage 1960s 6922/E88CC, and 7308/E188CC Amperex, Siemens, and Telefunken tubes vs. current production EH or Sovtek tubes? Well....
.