Those characteristic differences hold up well below clipping… I am never listening at levels that cause clipping.
I had a friend with big McIntosh MC-501s. He liked to listen quite loud but we never went beyond 50 watts and rarely above 10 watts on his Thiels. At my preferred levels we never went above 5 watts or so. We had far better sound from those speakers with 25 SET watts…even at my levels where, by your explanation it shouldn’t be the case since we weren’t listening to clipping characteristics…as neither amp was clipping…definitely not the Macs. Repeated this with a dozen other amps…just one of many to sound better than the ultra high power, low distortion MC-501s.
I’m not getting your point , you preferred the SET what does this mean the Mac is a bad amp , not seeing how this random event negates anything ..
A bit you should know about power meters on amps , firstly you have to determine if RMS or peak , then if true RMS as most amp manufacturers today never allow true RMS or peak value readings..
Herve and a few do , DAG , PASS etc dont, customer palpitations aside ..
So did your SET beat the mac to your ears , believable , it doesn't change the facts as presented..
Regards
PS: BTW those macs have very little class ( a few watts ) A bias , necessary for proper harmonic structure on instruments and more so at low levels , not surprised of the results. Try a Vintage SS mac , it may be closer to the SET sound ..