it could be done more specifically and more consistently with an equalizer than with the chance
So true, why have an amp that can't maintain a flat frequency response, into a speakers wavering impedance load, you may as well have a graphic equalizer, at least with it you can pick where the boost and cuts of the frequencies are going to be.
Look below at the black wavy line, that is the frequency response you will hear!!, and that's into an easy simulated speaker load, a hard load will be even worse
This is the well known Prima Luna Prologue Premium 25w tube amp with very questionable current.
8ohm tap + - 7db!! frequency response, "a tone control"
https://www.stereophile.com/images/1116PLPPfig01.jpg
4ohm tap+ - 5db!! frequency response "still a tone control"
https://www.stereophile.com/images/612PPPfig01.jpg
Here is the Pass XA25 25watter with far more current that the PL above, it’s +- 0.1db frequency response. Virtually flat as it should be!!!
https://www.stereophile.com/images/218PXA25fig1.jpg
Cheers George