first time replacing the tube inside my tubepre and the manual says i should get the "12ax7" tube. when i searched at musiciansfriend.com i found some that were 12ax7a and 12ax7c. how are these different from 12ax7 and can i use them as replacement tubes?
Your manual used "12AX7" in a geneic sort of way, referring to the family of 12AX7. As redevelopements of tubes are designed a suffix is added to the original name, A,B, and so on. As in life, there isn't one standard for these suffix', so you'll see some oddballs as well. Generally, they refer to design improvements. Below are some web addresses to tube data bases.. Enjoy.
