"practices. It does'nt matter. The only thing that matters is the
resultant change in sound at the listening position when one element of a
system is changed. If there is a difference, then the consumer has a
valid purchase choice. If there is no difference, then spending $20,000
on a high end amplifier as opposed to a $200 amplifier offers no rational
reason."

Amen brother, and when only one thing was changed, a cloth covering
connections so which amp is active in a comparsion is unknown, the
differences disappear.