Seeking a Warm 12AX7 Tube for Preamp

@spacecadet65 how many hours do you have on the preamp? I ask because the original Matisse needed about 100 hours to sound good.  There is also some evidence from owners indicating that changing the 12at7 in this particular circuit has more impact than changing the 12ax7; and it looks like you have already infused some warmth on the 12at7 side.  Would hate for you to go down a rabbit hole of tube experimentation and substituting tube variants that may not be optimal in the circuit if the unit isn't fully burned in yet

@stereo_gen I had the Sovtek 12AX7 LPS in my Black Ice FX Glass Tube DAC as the tubes selected when I purchased the DAC from Black Ice. Those tubes sounded ok in the DAC and thought I’d try them in my Phono Pre and they sounded pretty bad. I put them back in the DAC feeling there might be something better out there and ended up trying some NOS RCA 5751 Triple Mica Black Plates off EBay for the heck of it and I was blown away… MAJOR DIFFERENCE !!! Much more musical, more analog sounding and for the price you can find these for they’re absolutely a steel of a deal.

@gotog I also ordered some inexpensive (but reportedly tested and matched) NOS Sylvania 12AT7 from a reputable eBay seller that will be in mid. next week. The preamp has been running for about a week. 2 days ago I received the new 12AX7 Mullard reissues and burnt them in overnight. After about 24 hours I sat down to listen a bit. And knowing the tubes needed more time, I just put on some music that I was not so familiar with. I've been wanting to explore some Chet Baker. I put on a mid-50s release of the Chet Baker Sings album. Before I know it, the album was over and I had not thought about the system at all. I think that's a good sign.

At this point I'm completely down the rabbit hole. For better or for worse. But regardless of where I end up. If nothing got better from here, I'm really satisfied! 

I really appreciate all of the emails and advice.