To assume recently-moved production will be the same as the original production is actually a big assumption.
In my experience (precision powertrain parts for the automotive industry) when production is moved to different suppliers that's exactly the time when you will have problems.
The combined knowledge of all the designers, production supervisors, assembly labour has been left back in St. Louis.
Faxing a circuit diagram to a different manufacturing location is no guarantee of the same item being produced in the same way with the same results. Even if the whole assembly line was moved, it's likely that the order of assembly, and methods of manufacture will not be the same. Even if they were the same it's highly unlikely that they are ordering the same parts, with the same values, with the same performance characteristics as the U.S. assembly operation did.
The result is an amp with the "Ampeg" badge on it, but it could be built very differently and could have quite different components in it. How does one therefore, expect it could even sound like an Ampeg, nevermind have the same quality.
I'm not bashing any particular country or people group. I'm relaying the experience of anyone who's been in manufacturing. When you change things, things change.