I'm using a Primare P30 pre/pro in my 2-channel system. I've compared the P30 side-by-side in my home with the Ayre k3-x and Placette Active Linestage and a few lesser tube preamps. Neither the Ayre nor Placette are slouches in reputations and reviews.
Although the Ayre and Placette had some nice characteristics, it was a surprisingly easy decision for me to keep the P30 for it's overall 2-channel performance and presentation.
Besides, owning the P30 pre/pro confounds the conventional-wisdom of those who think a 2-channel preamp is automatically musically superior.
Primare is a little known Swedish company with a music first approach. The P30 retails for $3500 to $4000 and offers true 100% analog processing in by-pass mode.