Frontiers preamps. Even the least expensive line 1 has the same build quality and features as the cost-no-object (almost) line 3.This is a feat in itself. Full featured yet musical. Not your typical tube sound, but very exact and neutral, the way it should be ! I own a Line 1 with the McCormack DNA-225, I have looked hard to get the perfect match. After auditionning the line 1 and 2, I got a line 1, springing instead for the valvo tube upgrade. It captures the qualities of the McCormack amp nicely. Good luck! Hope this helps. Very nice built-in tube headphone amp by the way.
