Well, someone has to keep the flame burning...
I noticed that I was getting some slightly variable performances with the S2, ranging from mind-bendingly good to kind of blah, and I contacted Donald North, who suggested that my AC power might be chintzy. I've never had good luck with fancy power cords—in my experience, they always change the sound, and not usually for the better, often constricting the dynamics, aka the life-flow of the music—and I mentioned this to him. He wrote that he'd had a similar experience, but suggested I try either a high-current transformer or the first generation Shunyata Hydra power conditioner. I haven't had a chance to listen to either, but got my hands, somewhat reluctantly, on Shunyata's entry-level cord, the Venom 3. Even the name sounded cheesy.
What I heard definitely wasn't. The change in the sound was so significant that I really couldn't make sense of it at first. There was more tonal color, much more bass, less noise, and somehow everything sounded more ordered and cleaned up. And oddly, the dynamics, if anything, were improved. The emphasis did seem to shift slightly lower, toward the bass, and the timbres were richer. This was lovely with the HD800, which needs a rich, relaxing source to not sound wiry. And the variability of the S2's sound definitely decreased. Incidentally, I also tried the Shunyata cord with my Shindo preamp, and the results were much the same.
Lastly, I noticed that the S2 is fairly sensitive to vibration, but the Vibrapods I used under it had a tendency to flatten and stop working. So I tried Symposium Rollerblock Jr's, and everything got bigger, smoother and bassier.
These two changes (as well as the Cardas 4-pin XLR cable on the HD800) have turned the Sonett 2 into a consistently engaging and exciting listen—they've made the sound something like 50% better. No exaggeration. I suppose the lesson is to not forget to think about vibration and AC quality in a headphone setup—an relatively inexpensive way to have dramatically more fun.
Edited by mink70 - 12/2/13 at 6:58am