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

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

I have the same preamp and after trying several tubes, I ended up using some NOS RCA Cleartops. I even bought extra when I heard that Brent Jessie was closing. Having said that, I have never gone wrong with Amperex NOS.

All the best.

@curiousjim You have a fantastic system. I think your (& my) tube selection is more driven by our speakers. AI describes your G5’s as …substantially larger, deeper scale of sound with an incredibly lifelike midrange and a more forgiving, lush acoustic character. My Ref 3’s: hyper-analytic, modern presentation where pinpoint acoustic accuracy, phase coherence, and a ruler-flat frequency response are your top priorities.
As I stated ar the outset, those were my priorities, but now I want to warm things up without changing my speakers.
AI thinks more revealing tubes (your RCA cleartops or Amperex or my Siemens or Tele’s)) are perfect for your G5’s. Warmer (My Brimar’s or Mullard) for the Ref 3’s. Ergo, the Mullards. Thanks!