Which Preamp Tube is most consequential: Input or Gain


I've just gotten a pair of 1950s Tung-Sols for my Schiit Freya to replace two of the stock Russian NOS 6SN7. I will try them in both positions, but is there a typical position of more impact in terms of rolling preamp tubes in the input vs. gain positions? Thanks for any experience you'd like to share.
peterf6
@peterf6 , ok thanks for your comments. That’s a different layout than preamps I’ve owned. Typically, tube circuit is L R in front. 
And of course, Ralph (atmasphere) is correct.


@atmasphere and @lowrider57 Thanks for that. I know zilch about preamp design despite having tube gear for 40+ years. Isn't the input side a balancing and follower for gain? Why is the input the place to start? I'm seeing it play out in my roll, but curious...
The input is where the circuit has to get it right. It doesn't matter how good things are downstream if the input fails to do its job as best it can!