In reply to:

There's no way that an amp can affect the soundstage during the amplification process.

John, to be fair, shouldn't you have said "There's no way that a properly designed amp can positively affect the soundstage..."?

After all, an amp is only supposed to take the input signal, make it louder, and nothing more. If it's badly designed, couldn't it alter the original soundwave in ways other than amplitude?