Best 12AX7 for CAL Alpha

I agree the Mullard CV4004's are great! I also liked the Telefunken(ribbed plate) 12ax7's.

Has anyone tried a set of 5751's in a CAL Alpha? Results?

I loved JJ Tesla 12AX7s on my Alpha. The stock Chinese tubes were a little faster, the Teslas richer. I also tried GE 5751s and was not impressed -- to slow, too golden sounding. I found myself longing for the fast Chinese tubes.

I have tried the GE Jan 5751, CV4004 and Sovtek. To me 5751 is the best sounding so far. As detailed as CV4004 but more warmth and a little laidback.

While the 5751 is not always a good substitute for the 12AX7, it does very well in CAL DACs. An inexpensive and well-regarded 5751 is the Raytheon. These can be had for around $20 each at places like Tube World and I prefer them over GE JAN grey plates. 5751s have less gain than the AX7s.