If you have some contact cleaner you might want to lightly spray the pins and work it in and out of the socket a couple of times. It could be making poor contact due to slightly oxidized pins. If that doesnt do it it might be a dud. Bob
Tubes don't need to break in. Much the opposite actually, they have a usable lifetime that can only be reduced. Possible you got a bad one, especially if you got from ebay or a tube vendor that doesn't test their tubes enough.
If the amp was good before, and is now making noises, the culprit is almost certainly what you changed, which was the tube.