Seeking a Warm 12AX7 Tube for Preamp

What preamp did you purchased? Maybe consider getting the lower gain NOS 5751 , they are more expensive than your under $100 price point, but it might be worth giving Brent Jessee a call he does have GE 5751 premium at $110 a pair , or GE 5751 greyplates at $150 a pair and see if they fit the bill for you. He does have other 5751s but they are more expensive.  I use 5751s in my Line Magnetic 518IA integrated as 12ax7s were a bit too much for my ears in it. On the otherhand I prefer 12x7s vs 5751 in my Finale Audio integrated.

I agree looking into NOS 5751 tubes since I use a set in my preamp section. I would contact Brent Jessee for advice since he stocks many 12AX7 type tubes. He has some matched sets that are a bit over $100.

In my profile system page there is a chart for NOS small signal tube ie 12au7,12ax7 etc. its very handy for what you're asking. note its labelled 12au7 but it's the same for 12ax7, 12at7,12au7.   

OK. So I have to come clean... I made an impulse purchase. I've been enjoying THC edibles. And a few weeks ago I got an email about a Chi-Fi option. It is one of those "clones" that's based on a venerable old model who's patent has long since expired. So I bought a unit that is modeled on an old Matisse tube pre. It uses (2) 12AT7 and (2) 12AX7. I bought some new Mullard Reissues (12AT7), and I got a deal on the 12AX7 (new JJ). All from Viva Tubes.

https://www.ebay.com/itm/224885709348?var=523754766478

The preamp is shockingly well built. And sonically it is doing some very nice things. Very quiet noise floor, great open sound stage, and wonderful detail. But tonally, the balance is a bit thin, and the upper mids and higher frequencies are "shouty."  So I'm looking for something a little more warm on the top. 

Brent Jessee has Matsushita made 12ax7 that are very similar to Mullard construction for $110 matched pair. They are listed as: “12AX7 / 7025 Selected Dynascan, Allied industrial or Red Tip Low Noise Japanese made” on his website.

Otherwise, Mullard reissue should work for you.