Latter on appeared the active high gain phono stages to drive LOMC in exclusive way with no facilities to handle MM/MI cartridges, even those LOMC phono stages cames ( even some today ) with impedance load different values choices coming from 100 ohms to 1k ( more or less. ) where no one came with the option to choose 47k.
This statement is misleading. It is correct that some of these phono sections that had/have switchable input impedance did/do not feature the standard 47K, probably on account of poor RFI management at the input of said phono sections. That does not change the simple fact that 47K is indeed the industry specs for cartridge loading.
