A rather interetsing subject om KT88/90/120

Being eaten alive with suspicion that a particular quad in one of my amp (which is nothing short of stunning) - a KT90 quad is however responsible for the ever so gentle roll-off in the highs - shorter cymbals, with slightly quicker decay, and less air. Came across this :

https://edenaudiodesign.wordpress.com/2017/04/01/rolling-the-kt88-kt90-and-kt120/

Your thoughts ?