Best of current 12ax7?

I really like the GE 5751 NOS. I use it in my ASL headphone amp. This tube is a direct replacement for 12AX7. For new 12AX7's try the Tung Sol. (very good for the price)

You need to be careful with using a 5751 tube in place of a 12AX7. The 5751 has only 70% of the gain of a regular, typical 12AX7. These work GREAT in some gear, but it really depends on the circuit design. If they will work, they are indeed excellent tubes.

For new production 12AX7 tubes, I have used and really like the Mullard reissues and for a little more money the Psvane 12AX7s or the Sophia 12AX7s.

Hi Rja

With a tube phono I really like the Sovtek 12AX7LPS tubes and the newer Mullard CV4004/12AX7 tubes.

With a Jolida Tube DAC 2 I really liked the Genelex Gold Lion 12AX7 tubes.

In my Jolida amp my favorites are the JJ 5751 tubes, and Ruby 12AX7AC7 HG+ aka TAD 7025-S and Preferred Series 7025.

Sorry if I'm confusing you. I enjoy all of these tubes and haven't had issues with SQ, build quality or endurance. A majority of these tubes were purchased via Doug's Tubes, Jim McShane and Upscale Audio. That may be why I haven't had any issues.