Jeff, The /ECC83 would be the 12AX7. FWIW I always pull tubes one at a time, clean it up and stick on a piece of masking tape with tube number and ID. When you got more than one of a number this allows getting each back into its original socket (sometimes reduces re-alignment). Have fun with the '16. 74, Bob/WB0AUQ/brainbol at idir.net