Please help me chose a tube preamp

I have used the Calypso and then the Calypso signature with the Aesthetix Atlas signature amp for about eight years and love the combination. I would make sure that the Calypso output impedance matches well with your amp. In addition the Calypso will not give you a lush tubey sound like a CJ preamp. 

I am with @sgunther, as good as Calypso is, it just doesn’t have the lush tubey sound. With Calypso, you get a very nice balanced and neutral sound, kind of best of both SS and Tube worlds.

I end up trading Aesthetix Calypso for ARC LS28. In a highly resolve system, you just can’t underestimate the virtues of a dedicated preamp.

I use an Aesthetix Calypso with an Aesthetix Atlas. A great neutral combination. My system is posted if you want to see the other components.

I have had an Aesthetix Calypso and Rhea (phono stage) for over a decade and halfway through I upgraded to the Signature version of both, and am very satisfied. They both lean toward neutrality without sounding dry or lifeless but, a perhaps better way to explain them is to say they are not overtly coloured, presenting a large, open, well detailed soundstage with plenty of air. Little bad can be said of these as I believe they punch way above their price point, are very well thought out and constructed, and Jim White and associates run a really good, customer centric organization. If needed, they will take excellent care of you. 

I heard a pair of ProAc's with Aesthetix amp and pre- I don't remember which model- but they sounded excellent. I don't think you would go wrong with that manufacturer.
Another manufacturer, Atma-Sphere, makes a killer preamp. My MP-3 is everything I could want.
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