Different tubes, different companies, active devices, of course there is a difference. And as they break in there is a difference. Real reasons, and not all unmeasureable.
12-09-14: Omsed
Well apparently I did not make myself clear, sorry about that.
Same manufacture, same tube construction, just different years of manufacturing. Example, the Amperex PQ white label 6922 vs. the later manufactured Amperex orange label PQ 6922 tube. They do not sound the same.
The Seimens 1960s all grey plate CCa tube vs. the later manufactured 1970s CCa tube. They definitely do not sound the same.
Can the differences of the same manufactured tube be measured with todays test equipment? Can the differences be heard by the human ear? Oh you bet. But maybe not by all human ears....
Cable direction? Totally different proposition.
Maybe to your ears heard on your audio system.
But you should not try to push your beliefs and your limited ability to hear any difference on everyone else.
....
and I suppose after moving them they have to "break in" again.
Well that could depend on how the cable was constructed/manufactured and the type of dielectric materials used in the construction of the cable.
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