Tube imperfections

I can just about guarantee there are differences you will be able to hear if you listen for them. You will probably also find some that make a big enough difference to be obvious. You might even find one that is so obviously better it was worth the money. But I can also just about guarantee this will not happen on the first try, if ever. Almost always what is much more likely is you will go through three or four modestly different results, just enough to tease into keep trying, maybe after four or five you get one good enough you feel maybe this is all worth it, maybe this next one....after a while it starts to seem you're getting closer and closer wow these tubes really are distinctive. 

When really what is happening is you're getting better and better at the fine art of discerning differences between tubes. So that if one day you do find the white whale it really will feel like a white whale. Even though at the end of the day the difference between the very best and the very worst of them all is less than one $160 Synergistic fuse, only you had to spend five years and $1500 to figure this out. This being more cognitive dissonance than most can stand you inevitably decide it was all totally worth it. And round and round we go.....
Another thing you might learn along the way, which nobody mentions, is instead of tube rolling you could be diode rolling. Because, let me tell you, there are massive differences between diodes. They cost a lot less. Changing them pays bigger rewards by far. And its just about as much of a crap shoot. But it calls for soldering skills. So nobody does it. Otherwise for sure if someone ever invents a diode you can just plug and unplug then by God audiophiles will all be into diode rolling. 

Oh wait- tube diodes! Nevermind! lol!
https://www.youtube.com/watch?v=K0gSNTAA0_Y

Tubes work by controlling the flow of electrons between two plates. As long as the plates are aligned properly relative to each other it really doesn’t matter how they are positioned relative to the glass. The glass is there only to enable the vacuum that allows the whole thing to work. It can be any shape, angle, what have you.

That said, if it bugs you it bugs you. Since they are willing to exchange then you simply have to decide if it bugs you enough to be worth shipping it back for another one.

Tube rolling in my book is pretty small beans. But there’s guys for whom finding the great white whale is what makes life worth living. Which one you are you will probably only learn after wasting, er I mean spending enough time and money on it to find out for yourself.