12AX7 tubes for the phono stage of VAC Avatar SE integrated.

wharfy, yes, I know, I bought tubes from Brent of Audio Tubes. He is very good, and pleasure to deal with. Replies to emails on Saturday and Sunday. I might talk to him about it later as well but first I would like to hear what audiophiles think. Besides, he is currently out of stock of reasonably priced Mullards. RCAs and Amperexes are available.

tomcy6, yes. Perhaps I could order a pair of Amperex from Brent and give them a try. I would have to burn them in for 100 hours, and if I don't like them enough send them back. That would cost me 20% of their price plus shipping both ways, which would be a little over$100 in worst case. Not a big problem if there is no other way.

I read extensively on another forum where guys talk in details about tubes for their amps and it is now more or less clear to me. In my amp and for my taste it's Mullard. Amperex long plates and Raytheon black plates would be bright, regardless of their strong points, and RCA black plates would be a bit too thick. Sylvania long black plates have exceptional clarity and tonal balance but they can be microphonic and they lack the sophistication and depth of Mullards.

@inna 

Your query got me to look through my signal tube stash. In a box labeled 12AX7 is a pair of NOS Matsushita, black plates, that were manufactured using Mullard tube tooling equipment. I bought these from Brent Jesse at his recommendation.

He also recommended Japanese manufactured 12AD7 because they are low noise tubes, used for recording. I didn't pursue it even though it had the same specs as 12AX7.

You may want to try the cryoed tubes from CryoTone. I have bought the 6SN7's. They are extremely quiet. And there's an extensive trial / return policy. They're not NOS, of course.