Yes, the mastering aspect is much clearer now! I've had no experience actually sitting in the seat of a recording engineer and I'm sure that was displayed in my previous post. Regardless, the process is much clearer now that I've got an explanation in front of me.
So the EQ is applied directly before the speakers, which makes a lot of sense as you'd need it to be applied to everything before the speakers themselves so that the same EQ is constant regardless of the source before it. Perfect. Does my EQ in the analogue environment vs the digital environment theory still stand? Briefly, EQing in the digital domain will have less negative effects then doing so with the analogue signal itself? It seemed that EQing the signal in the analogue environment is a battle of compromises whereas that was much less of an issue when doing the same in the digital environment. So you're taking the signal from the amp, pushing it through the EQ and out to the speakers? This signal is all analogue correct, as in the eq is not changing it back to digital modifying the signal and then sending it back out to the speakers in its altered analogue form? I'm not sure if this theory holds water or not.
Finding that perfect set of a equipment (and I wholehearted agree here) is like finding a needle in a haystack, but that brings me to another question. Given the amount of different gear you've the ability to pick from, why would you choose a 5000 dollar amp over a 500 dollar one? Lets say you have speakers which are dead flat, you've eq'd everything to where you'd like and you have a modest setup. Technically you're hearing the music as it was intended, accurate to how the studio heard it. Are you searching for a more appealing sense of neutrality in your playback when you choose the 5000 dollar amp? It seems that since you've applied room correction and eq'd the output before the speakers there's nothing left to do and a modest setup would be all you need since the amp's output is going through your carefully calibrated EQ. How can you now justify the more expensive amp?
"Now, let's say that you prefer a little bit of coloration overall in one place or another in the curve. The odds of finding equipment colored to your particular taste is like trying to find a needle in a haystack. Some people like a 5dB bass boost at 100Hz, other people would prefer a larger boost in the sub bass- say a 15dB boost at 40Hz. Still other people prefer "in your face" mids, U shaped curves with lots of bass and treble, or "detailed" or "warm" treble. It's just not possible to have DAPs, CD players, DACs or radio tuners all adjusted to a different taste in sound signature. That would be chaos.
So they make everything neutral, and you apply an overall correction using an equalizer to make all of your equipment sound colored precisely the way you want them. EQ curves don't have to be flat. They can be any flavor of the rainbow you'd like, and you have complete control over how much of a coloration or how little you want."
They as in the equipment manufacturers themselves? I find that hard to believe but I may not be getting that pronoun's reference correct. I guess what I'm getting at here is that the amp, regardless of how neutral it is, has different flavors of neutrality or warmth or whatever. Some appealing to you, some not. So in effect you are picking an amp for what it adds to your system, in your case I'd assume your searching for one which adds the least amount of anything. Do you measure this quantitatively or merely use your ears? I'm not sure how'd you'd establish a baseline for neutrality given my assumption that not all neutrality sounds the same amp to amp. Conversely, your quote above leads me to believe that you can pick any arbitrary collection of equipment, eq the output to your flat response speakers and be happy with the sound you've created as it is accurate to what the recording engineer produced in their studio. The emphasis here is now shifted from subjectively picking equipment that you like soundiwse and instead picking equipment which will objectively make your system just run so that you can personally change the sound output via your EQ. The EQ becomes the keystone of your system's inherent sound, the rest is just there to provide a signal path, power, and other basic needs. Does this make sense?
To bring this back around to OPs post, you've a tube amp and a solid state amp which display the same numbers on paper (tough, if not impossible but let me use this fantasy for the purpose of the discussion); thus on paper the two amps should sound roughly the same. The same could be true of two solid state amps or two tube amps, how are you picking between the two assuming their specs are the same and assuming that your EQ is modifying their output anyway? There just doesn't seem to be any room for argument now as to which amp sounds better than the other as you've already pigeon-holed the sound how you like it regardless of the transmission line before the EQ.
PS, I guess I should be fortunate I'm not yet married as the wife seems to add another difficult variable!