I read the link and the author believes the amp needs to deliver 132 dB of peak SPL into the headphone. Is he trying to destroy his own hearing?
Classical music has the greatest dynamic range of common music types. And average to peak difference is generally around 30 dB. Even if we give it a 10 dB headroom, that means peak level only has to be 40 dB louder than average level.
Now, safe average listening level is around 65-70 dB SPL. Continous listening at 80 dB is enough to cause hearing damage. 70 dB + 40 dB = 110 dB. That is all you need. I recall 109 dB is what you would hear if you are 6 ft away from a concert grand piano playing loudly. A single burst of 120 dB sound is enough to cause permanent hearing damages. 132 dB SPL is suicidal...
Rock music has maybe 15 dB peak-to-average difference. So if you listen to rock loudly at 80 dB, which is dangerous by the way, the peak will only be 95 dB. Just because the music type is louder does not mean you need more power.
BTW, many headphones are not designed to withstand 130 dB blasting.
For those who want extreme loudness, Furman HA-6 can pump 20W into headphones.
Focus on the math not ultimate listening levels or you will get nothing out of the reading of.All about headroom and not as much the excact level you would listen at .
If there is is anything worse than running out of steam and clipping an otherwise proper solid state amp stage I don't know of it and running right at the edge of what you think you need is a recipe for that.