mulveling
First impressions of tube or component changes can be especially nebulous - because anything that the new component sonically accentuates can easily evoke a new emotional response that we can’t help but latch onto. This can allow us to experience our favorite tracks in a different light, perhaps even noticing parts of the music we hadn’t before. However on extended listening - we may notice the accentuation is really unnatural. We may even go back to our old component and suddenly that "new part" of the music is actually still there, we just hadn’t listened for it before because it wasn’t actually supposed to stand out ...I agree completely, and that is exactly why I think equipment "shoot-outs" are virtually useless. A component’s true character is revealed over time. Trying to assess it quickly serves no purpose and the result is prone to error.