Couple of years, completely different tube sets... I would speculate that they were probably on different rigs in different rooms also. Swampwalker, that's an interesting way of fairly balanced comparison. I'm sorry, yet I must take issue with your comments, to say the Aesthetix Rhea yields "average performance" and the Signature is "very good"... what prey tell would you surmise to be excellent?
It's funny that most journalistic review and otherwise find the Rhea very, very close to the IO which many consider one of the finest, if not for many, the finest phono stages of all time. I have owned the Calypso and Rhea for several years and compared them directly to the IO Signature, Atma-Sphere MP1 w/phono, and spent good time listening to Manley Steelhead, Sutherland Ph.D., Audio note M9, just to name a few and I find the Rhea as Robert Harley and so many others, outstanding.
Please understand, in no way do I mean this as a personal affront, yet I find your comment to be diametrically apposed to my experience.