I have Io Eclipse with two power supplies and additional line inputs. Up to now I have only used the stock tubes as supplied and matched by Jim. I do not have the time to do tube rolling. For best results, the two power supply boxes must be away from the main box as far as possible. I tried the Io in combination with various preamps like the Gryphon Pandora, ARC Ref 6, Halcro DM10, but still prefer the Io as a stand-alone. Turntable is a SME 30 with SME V arm, Dynavector DRT XV1t and Furutech Silver Arrows III XLR phono cable. On the digital side I use dCS Vivaldi 4 box, plus Network Bridge feeding the additional line input on the Io. Power amp is a Gryphon Antileon EVO, speakers are Vivid Audio Giya G1s. Interconnects are Gryphon VIP reference. I absolutely love the combination. Soundstage is massive, tonal balance is spot-on and the system sounds very natural. The synergy between the Io and Gryphon surprized me. I used the Gryphon Pandora pre and Legato phonostage before this, but got tired of the combination after a while. The Io also synergizes well with the dCS Vivaldi.
The Io is an impressive sounding phono- / linestage, provided that one can live with the heat generation (room gets hot with Io and class A Gryphon), lots of rack space required, no remote volume control and strict operating procedures that must be adhered to.