Ok, mis-understood the question....
I believe that Ron-C, here, has mentioned that the same machines are still used to wind the Autoformers and that the same 2 operators have done this same job for the last 30 years or so.
While this is a testament to Mac's commitments to the autoformers, I'm pretty sure that the basic technology really hasn't changed that much. In addition to the MC-225's I have, I also use an HK Citation II power amp which has quite wide-bandwidth output transformers, both amps perform quite well given their age.
The technology on transformers has been worked out, it remains a question of how much you'd like to pay for quality devices. I'd say McIntosh has had the details nailed down for 50 years.
Hope this answers the question.
Cheers,
David