Any experience with Thrax as a preamp?

I am considering replacing my beloved VAC Phi Beta preamp. Possible contenders include the Thrax dionycious, Constellation Audio entry level, Jeff Rowland Corus, or upgrading the VAC for an used Renaisance iia. I will have a chance to audition the Thrax, but several of the online reviews have not been kind to is quirky volume pot, and comment on lack of full, robust sound stage and warmth. I know that Thrax is still highly regarded, but have not seen any specific folks on the forums with Thrax who provided insight into its sonic character strenghts, and flaws. I am looking for a pre with a pair of outputs in rca, as I use one set to output into my powered JL Fathom sub, other to amp input. Helpful comments would be welcome, and appreciated.
Happy New Years!

loved the dartZeel tubed pre

What dartZeel TUBED pre are you talking about?? I thought dartZeels are all SS.
Had an opportunity recently to listen to the Thrax Dionysos in our system for a couple wks.  Brought beautiful crystalline clarity in upper frequencies, very fast transient responses throughout.  Nice boost/balance to mid-bass frequencies.  Definitely hearing subtleties that I've not yet heard in reference recordings I've used for yrs. However, don't feel it has particularly great holographic imaging, in say comparison to the Atma-Sphere MP1/MK3.3 that we also auditioned recently, although the Dionysos is certainly quieter w/ blacker backgrounds.  Dionysos also comes across a bit more forward presentation.  Biggest issue I dealt with was attenuation. Volume control is not subtle - in fact 0-1 is a quantum leap, and realistically could not bring it past 3 w/o bringing pictures down from the wall.  Not sure what's up with this, but perhaps others w/ Thrax experience could enlighten me?  
Know this is an old thread. Noted mbump eventually upgrades to VAC sig preamp.

Mbump, would you mind to share what other preamps you have tried and what made you decided to upgrade to VAC sig?