I had a Ref 1 once and it had the stock tubes in it from Audio Research. I loved that preamp except for a mid-bass bloat sometimes that was too irritating. I got the Ref 2 Mk2 and the bloat disappeared. If not for the bloat, I prefer the Ref 1 over the Ref2 mk2.
Maybe tube rolling would have solved the problem....I just didn't have the patience to experiment with tube rolling. Funny thing though, I didn't get the mid-bass bloat when listening to my tuner though. My tuner took on a whole 'nother dimension with the Ref 1. The Ref 1 sounded better with my tuner than the Ref2 mk2 does now.
