Replacing 12AX7 to 5751 for pre-amp

I just went from a 12ax7 Tungsram ( and many other 12ax7's ) to a Sylvania 5751 3 mica black plate ( Yellow Label ) in my newly Upgraded Thor Audio Linestage and must say its the best 12ax7/5751 I have ever heard ( in my unit ).Sweet,a touch Forward,Dynamic and incredible inner detail.They are not cheap and are hard to find ,but once found well worth the effort and cost...

Try a set of Full Music 12AX7's. I find them better than the Sylvania black plate trip micas. Sold the sylvanias.

You can't substitute 12AU7 or 12AT7 for 12AX7. There are many 12AX7, 5751 or 7025 that you can try. Good Luck.

I have tried all the 5751 tubes in my 834p phono stage and found the Eat 12ax7's are superior. Not cheap,but the best.

Tim

Be aware that you could raise distortion issues with certain circuits by this 12AX7 / 5751 substution. While electrically it may be benign, it is no assurance of optimum sonics. This info courtesy of circuit designer Ron Cornelius via Audio Classics concerning research on my Mac C-22. Good Luck