Theaudiotweak, knowing what little I do about tube circuits, I think the answer is yes. I guess this most true for a tube where many manufacturers made it, such as the 6SN7, or where there are many close substitutes, such as the 6DJ8. As the old adage goes, at least with tube circuits the customer can chose which tube he wants; in solid state designs he has no choice.
I don't understand why I am being asked this, however.
I don't understand why I am being asked this, however.