Hello. Regarding the U47 tube topics, I have found a lot of interesting discussions, but none about this replacement valve I found on the internet : the RV14m, which is supposed to be a vf14m replacement tuve with no need of any modification on the mic. Does someone know this tube ? If yes, how does it sound ? Is it comparable to the VF14m from an "audio" point of view ?

Secondly, a lot of people have stressed the importance of an original M7 or K47 capsule when acquiring a U47 mic. Obviously, with the time, those kind of capsules have to be restored. But how one would be capable of knowing if the capsule (let say a M7) on a U47, is original or is just a copy ? In other words, is there any way to authentify a M7 or K47 capsule (Neumann brand on it, serial number, etc.) ?

I already thank you for your help.