Additional Preamp Tubes


I am looking to purchase an additional matched pair of NOS tubes for my PS Audio BHK preamp. I currently own Brimar CV4003, Telefunken Medicals & Siemens Nickel Plate. 
When I began building my system 3.5 years ago, I wanted revealing - accurate. Now I want a tube that is more musical / warm, similar to the Brimar’s with a touch more warmth. 
My system: Aurender N150 > Briscati M3 > BHK > Moon 760A > KEF Reference 3’s. Rega P8 / Hana ML > Gold Note PH 10 on analog. Cables are Kimber Select from sources & Transparent Ultra’s pre > amp > speakers.  
ChatGPT recommended Mullard CV4003. There is a pair on eBay from Valve Tubes. Please let me know your thoughts on this and other potential tubes, and if you have any experience with Valve tubes. Thanks!

signaforce

If anybody is still listening, you might consider some new production tubes. Ray's Select 12au7 are nicely balanced tubes. I also tried new production Mullards. Currently I am using PSVane Horizons (GASP!) in my Backert Labs Rhythm. If you want a more controlled sound with lots of depth, give them a try. At 65$ pair from Amazon (Gasp again!!) not much to lose. 

+1 on Psvane!  I've had terrific luck with Psvane tubes.  For new production tubes, they come pretty damn close to NOS, (and sometimes better).  Highly recommended.

Still listening. My BHK pre came preloaded with PSVane tubes. Since I already had my current tubes from my Rouge RP1 that matched my BHK (part of the reason I bought the BHK), I changed them out pretty quickly. 
Most modern tubes are Russian, and refuse to buy Russian, even if they were the best… and IMHO they are not. 
My NOS Mullards arrive from the UK on or about the 22nd. I look forward to trying them. Thanks