Seeking Suggestions on Preamp Upgrade (CJ, Aesthetix, EAR)

The issues I heard about were from a dealer who had purchased Aesthetix for his personal use....he wasn't an Aesthetix dealer.....It was about 2 years ago......overall, he has been much happier with the Zesto, he became a Zesto dealer after purchasing their preamp.......at 5K used, you should be top of the food chain in terms of a tube pre.....you can do a lot better than Aesthetix.......

There is a Leto on gon for around 3500 now

If you want to have some real fun, get the Precision Fidelity C7 on gon now....these are like hens teeth, hardly ever coming up for sale.....one of the most musical preamps ever made..I owned a gold one in the late 80s, biggest regret ever...selling it...this guy wants around 1300 or so.....There is also a few CJ options on gon right now.....

Hi  david, 
you have asked an open question. Soon enough, there will be just about many different preamp recommended to you. 
what is your music genre and your sound preference like? i.e laid back, relax? euphoric? vivid? big voice , wide soundstage?

there are many different preamp that will be good only in certain aspects of audio reproduction. It's very difficult to achieve absolute detail with richness and tonally accurate plus wide open soundstage if you listen to majestic performance like in a classical recording. only a handful with a heavenly price tag  preamps can do well in everything.
-phil

Hi, Phil:

Nice suggestion.  My original intention is to confine the discussion within very few items based on the paper study I did.  I have omitted some very obvious major brands based on my first-hand experience.  I prefer a warmer sound, with laid-back, live-like, classical music remaking.   I go to live concert performance pretty frequently.  To me, a lot of equipment sounds too bright and too articulate to mimic the string groups in an orchestra.  Of course, this is only to me individually, and may not be applicable to majority.

My current system is free of listening fatigue - I can do a continuous listening for hours with peoridic performance or harpsichord of Baroque music.  But to compare to a live performance, there is still a distance.  I am not talking about personal emotional involvement, just pure acoustic quality.

I cannot afford the heavenly price tag equipment.  Just acoustic sound of classical music of natural sound, so the bass requirement (I rarely listen to music played by organ) is not very demanding but mid-range and high frequency may be my major concern.

Thank you very much for posting to clarify the purpose.  

FYI:
  The prevailing rule of thumb is that the input impedance of amplifiers should be 10 X greater than the output impedance of  preamplifiers.
  The Pass XA30.5 input impedance is spec'd at single ended: 15K Ohms and at balanced:  30K Ohms.
  c-j recommends an amplifier input impedance of 20K Ohms for all of the above mentioned c-j preamps. All c-j's are single ended only.
 The Aesthetix Calypso suggests recommended amplifier loads of single ended:  10K Ohms or greater and balanced:  20K Ohms or greater.
Couldn't find anything specifically re: the EAR 868, but Ear does suggest looking at the EAR 912 as this what the 868 what based upon. The EAR 912 output impedance is spec'd at:  600 Ohms.
 The Zesto Leto  output impedance is spec'd at:  150 Ohms both single ended and balanced.

What you need is to purchase a reasonable good preamp that response well to tube rolling. Most people use tubes to fine tune the degree of warmth.

EAR , Mapletree audio and Joule Electra are some of the tube pre that i find may have more warmth compared to CJ , ARC, Allnic and alikes.. do be aware that within its product line, there are also some difference in their sound characteristic too. PrimaLuna is another suggestion, however, personally i feel it's does not sound laid back, much better for music with singers. 

you have to judge for yourself how distant sound you feel that's right for you. There are many preamp that provide warmth but it's much more difficult to strike the right balance mix of detail, articulation and warmth that suited to your taste, hence tube and cable rolling sometimes can be quite handy. 
-phil