Each current production 12AX7 on the chart has information about the gain structure and noise rating as well as a brief description about the tonal characteristics for each tube.
One of my favorites is on the list…the Sovtek 12AX7LPS. I really like the gain, texture and vibeyness…(is that a word..?).
Any way it’s a cool little chart that Orin, Kurt and the good folks at Amplified Parts have put together.