Well, I understand your apprehension, but I think that people with both versions have experienced this. SOME of that could well be bright recordings, in my case they are not generally considered bright, in fact I have never heard anyone call them bright, but even with that, I would think that the man who designed the Yggdrasil has done an amazing job on the upgrade. I think since with a Cardas cable it sounds fine, it's not bright, and without it it's not just bright, but also distorted, it has to be a cable compatibility issue. If your not having issues now, I am guessing that you won't after the mod, but if you do, go to a Golden Cross or a Golden Presence cable and that should fix it. I have not gone back and done any cable comparisons since I put it in and allowed it to settle in which it definitely needed as it started out bright on recordings that were not bright using my other cables, that cleared up quickly, but it did take a couple of days for it to really open up. Anyway, I have a set of Triode Wire Labs Spirits coming in a few weeks, I know a guy who has the Yggdrasil and the Freya as do I, and he uses Spirits with good results, and they are supposedly better sounding, as he has owned both. Anyway, I am not convinced that the problem is actually with the Yggdrasil because if it was, cables shouldn't effect it. A sensitive system likely just allows you to know that some cables have issues. I am making assumptions mind you, but I wouldn't hesitate getting the upgrade, your electronics certainly will allow you to hear a difference.