I bought some RFT ECC83s off a reputable guy in FLa to put into my Marshall 2203. Anyway, Took them to my tech to install and my tech (he sells tubes :>)) I know what your thinking, said that these particualr RFTs have thinner plates and hence will make my Marshall sound a little thinner than say an RFT 12ax7? Whats the differance? I dont really understand this? Cant I just put these in my amp. Im having some TUng sol 12ax7s put in the amp for now but when I get the amp home I was gonna switch out the TUng sols and try the RFT ECC83s anyway just to hear the differance. Been researching the RFTs and a lot of people like them. Did I buy the weaker ones as in the ECC83s and not the 12ax7s? THx for any info here. Very confused.