21fb j p22

[Yamamaya42]

Well, I don't believe that a grade A will last longer than a grade C, or vice versa, they were all most likely made in the same plants, from the same materials in the same way by the same people, it's more like a matter of that any given build of tube where the electron gun assembly, and / or shadow mask to screen placement was just a micron off of what may be considered grade A tolerance, making it harder to get ample convergence / purity w/o going beyond a set boundary, or, like in the case of the tube I have, a minor minuscule flaw in the phosphor or shadow mask that causes a tiny blemish that most won't notice unless you really look for it! :P