My instrument tuner can't detect a difference either!
Atmasphere,
I think Im realizing why it is so difficult to absorb what Im claiming.
Not to make things worse but I should mention that my work with amplifiers has taken place at microscopic levels. I have studied the behavior of circuits as they operate or are set into motion.
Since this is far below the radar of test equipment it is done in a theoretical realm
The changes in gain that I have tried to give as examples are gross exaggerations done in order to make a point that you can recognize at a large scale. In fact the changes in gain that I deal with are typically 1/100th of a db. or less. You will never see this with a spectrum analyzer or oscope. The tiny changes in gain however will definitely manifest themselves as obvious to the listener when your brain detects the unstable placement of a given sound object in the deployed sound field.
Roger