lol - of course this is excellent info...

...but i indeed stay unmoved: i never wanted to know about the innards of my gear (well, a bit i had to learn so i could maintain my analog desks) and never became knowledgeable enough that i could draw any meaningful conclusions.

regarding the 421, i did have three old ones (grey version) that measured so far apart that i didn't even want to use them on toms anymore so i bought a bunch of the newer versions - not because i liked them much but because some guest engineers or drummers did (and occasionally also a guitar or maybe a trombone player)...

...but why use a large dynamic mic with a weird behaviour when i can have smaller dynamic mic or condenser mic with a much more favorable behaviour?

anyway, there are three use cases in which my 421's still come into play: bass cab and leslie low (out of habit) and occasionally on trombones in big bands (if i've run out of all other options) - oh, and some dictators/autocrats still use them on press conferences! ;-)