PrimaLuna Dialogue Premium preamp owners!

Please help me. Looking for new tubes. I read that it is difficult to beat the stock tubes, but I am willing to try. I am currently running a Pass XA-30.8 amplifier, Harbeth Super HL5+ speakers and an Esoteric K-07 as a source. I listen to rock, jazz, classical. Love female vocalists accompanied by the piano as well. I want to avoid anything that will accentuate high frequencies or anything that may cause harshness in the upper registers. All that being said, I was considering Amperex Medical 12AU7, Brimar CV4003, Cifte 12AU7 or Mullard cv4003. Or something else? Thank you in advance.
I would be interested in the RCA Clear Tops. Amperex I'm not so sure because they are sky high and not sure if they are worth the money to be honest. Joe Tubes Lore wasn't a huge fan. However I'm sure they work well in some applications :)
I use Joe's Tube Lore as a touchstone; it is outstanding work by Joe and I agree with most of his listening experience. As always, room, rig, taste will determine what one settles on...the RCA Clear Tops in my Primaluna were very good, just not as good as Amperex in this case, but still a quality tube, better to my ears than Primaluna stock tubes. A good bargain NOS tube is Telefunken clone, labeled Ei, built in/on the same Telefunken machinery by Ei; also NOS not made any longer. I have those as well. NOS and used, but test as NOS. Best, Rob

samzx12 ;

If I remember correctly , and that is a decent sized if , the 6CA7 is the American

version of the European EL-34 tube . You can find a 6CA7 made in America at some of the tube retailors on the net . I have no experience with any of the American versions so I can not tell you if the Black Treasure's are that much better , from my personal experience . But what I could find out from others , they

are . 

Happy Tunes 

Mikirob message me sometime and let me know exactly what you will have for sale and prices please. 

Saki thanks for your thoughts. 
The Black Treasure 6CA7 much, much better than stock EL34 in Primaluna.