Hi all, I got a command receiver ,it seems to be a R-25 ,1.6 - 3.0 Mcs ,Black paint(lost), it has lost his ID plates and the wiring is the same as the scr274 series second if valve seems to be 12SK7 instead of the 12SF7 claimed to be by my ARC-5 manual. Are there different types of circuits for the ARC-5 receivers? TIA , Carlos LU8DOG Buenos aires , Argentina