12AX7 tubes for the phono stage of VAC Avatar SE integrated.

@inna 

If you want mids, NOS Mullards have the mid-range-to-die-for-reputation. I imagine older 12AX7 have higher-microphony issues. Thoughts?

Tubes for phono must be especially quiet and balanced. Similar to tonearm cable.

Amperex are noted for their midrange. The ones made in the Heerlen, The Netherlands factory are what you might want. They can come with different labels, mostly Phillips, but also others.

There was also an Amperex factory in New Jersey. Good tubes but not the same as those from Heerlen.

Amperex NOS, made in the Netherlands, is available from a very reputable dealer, from $200 to $450 for a matched pair. But would they be any better in my set up than Mullard or RCA ? That's the question.

There is also NOS Raytheon long black plate for $500 for a matched pair, from a different dealer whose prices are often the double.

Shuguang Black Treasure 12AX7LS from Grant Fidelity

First, I don't do Chinese, and second - they are not available.

Well, there is a matched pair of NOS Mullards 10M with gold pins for $799 obo on ebay. He sells them here too for $999.

That would probably be fine but too expensive for me.