Groove tube 12AX7

[tomo]

Does anyone know OEM of these Groove tube's 12AX7?

12AX7R :
12AX7R2 :
12AX7R3 :
12AX7C : Shuguang(12AX7-C9)?
ECC83-S :

Thank you!

[billyz]

normal Groove tube nomenclature would be: the R is russian made, The C is Chinese, the S probably Serbia.

[Firestorm]

The "S" is Slovakia (JJ). You have to watch out for the 12AX7 WA, WB and WC. The ABC don't have anything to do with manufacturing locale -- just descending order of gain.