Tube Pre-amp BAT, ARC, EAR, Sonic Frontiers

Thank you very much, Lapierre for your kind words and high marks of my system :-) Yes, Aesthetix Calypso is on my list also. I can meet it quite rarely so this was the only reason why i did not put it in my 1 post.
Well I will define my level up research :-)
Sonic Frontiers Line 3
BAT VK31SE or VK51SE
Audio Research LS25 mk2 or?
EAR-864
Aesthetix Calypso
Audio Valve Eclipse
now i also got very positive feedback about Belles 21A though I heard Belles 28A ref (although it is a solid state but remarcable pre!)
Indeed I paid so much attantion to synergy in my system. I've passed a lot of amps and couple of CD-players. Now I love the sound and do not want to spoil it with wrong preamp.
My problem is that I cannot listen to those preamps marked above. I live in Ukraine and here it is a problem. So the only choice is to read a lot then buy it and try it :-)
As i said earlier today I will listen to EAR 864 just to clarify for myself what good preamp can add to my system (i hope add, no subtract :-)
and then I will tell you about my influences.

Thank you

I will add art audio preamp on your list,I personally
recomend Art audio's preamp,for my taste they are very
musical,I used to own audio research preamp,and heard
tube preamps.And Joe is a very nice person to deal with.
Thanks Bon

Morning :-)
so i auditioned EAR 864 yesterday. What to say. Difference between Accuphase---EAR---Electrocompaniet and Accuphase---Electrocompaniet was not stunning. At first sight everythin' kept the same. In a while I noticed that sound without EAR became less natural and less involving.
Also EAR added sweetness so i would prefer to keep that natural and involving impressions but subtract sweetness.
Anyway now i am convinced that good preamp won't spoil my system synergy.
To say the truth my first candidates are Sonic frontiers, Aesthetix Calypso and Belles 28A ref (up to forum discussions they got mostly positive feedback)

Also EAR added sweetness so i would prefer to keep that natural and involving impressions but subtract sweetness.

Check out ARC LS-25MkII.

At least consider the Einstein. With NOS tubes, it is world class and very reliable.