Charles1dad - thanks, you make an interesting point, perhaps my preconceptions are wrong. But to my ears, the Io has the highest resolution. With the Einstein, I may not hear all the small sounds in Zappa's orchestra playing Waka Jawaka, but I get an immense sense of drive and purpose. This is information too. So it may be, you are right, with a superior component you stop thinking of details and resolution. It is "hidden" so to speak.
You also say: "the direct route appears to be omitting significant vital details of your recording. The Einstein is presenting the more complete music signal."
Well - not sure if the Einstein is more resolved or complete, they are both high quality. The main case here, rather, is that the Io needs a preamp to do its best. I don't think it is omitting anything, it is just not optimal as a preamp, even if it has volume.
It is like the Io is offering the "dots" but I need a preamp to draw the "lines" between them. There are always some dots lost (and some false lines) with the preamps I've tried so far, although less so with the Einstein. It is a give and take, as others here have commented.