5751 have 70% of the gain of the 12AX7s, or less gain than 12AX7s. Sylvania made both type of tubes. Lots of articles out there will confirm this.
You may want to try the link re: Joe's Tube Lore for more info on this and other questions you aked about the two tube types.
I note the author of the article reports in it, concerning the Sylvania 12AX7s,
The author of the article loves the Sylvania 5751 triple mica blackplates in its various guises (less so the Sylvania 5751 triple mice greyplates), but go ahead and read to article to find out more.
I've got a NOS pair of Sylvania Sylvania Gold Label JHS 5751WA triple mica blackplates currently in my Jolida JD-100, and another unused back-up pair of NIB Sylvania Yellow Label JHS 5751WA triple mica blackplates [1956 date labels] (these are the same tubes, as the article will point out), and couldn't be happier with the pair currently in use in my system. Happy tube rolling, and watch your wallet!
You may want to try the link re: Joe's Tube Lore for more info on this and other questions you aked about the two tube types.
I note the author of the article reports in it, concerning the Sylvania 12AX7s,
The rest of the pack - the Sylvania/ Phillips, GE, RCAs, etc.. are even worse.
The author of the article loves the Sylvania 5751 triple mica blackplates in its various guises (less so the Sylvania 5751 triple mice greyplates), but go ahead and read to article to find out more.
I've got a NOS pair of Sylvania Sylvania Gold Label JHS 5751WA triple mica blackplates currently in my Jolida JD-100, and another unused back-up pair of NIB Sylvania Yellow Label JHS 5751WA triple mica blackplates [1956 date labels] (these are the same tubes, as the article will point out), and couldn't be happier with the pair currently in use in my system. Happy tube rolling, and watch your wallet!