Well finally after what seems like an eternity I got the chance to sit down and do a side by side comparison between the new HD800S and my very own HD800s (no mods just in case you were wondering) . I got to spend some time listening to a couple of my all time favourite albums several times through on each and well...............
There is a difference but not a big one and probably less than I was expecting having seen a number of reviews by others (much more experienced than me) on this august web site. The difference at the top end felt as if treble shimmer was gone but not any decrease in treble output or energy. Let me be up front here and say that I have never found the HD800 too bright or thin or peaky or whatever other ills the infamous 6kHz spike is supposed to create. So maybe I am biased, but on that aspect I had no to conclude no preference for either headphone.
I would also say there was no discernible difference in stage width, depth or imaging that I could hear, and so once again I had no preference for one over the other.
Midranges to me seemed equally neutral although perhaps a tiny closer to absolute accuracy with the 800S but I'm not sure I would have picked it blind every time out of 10.
Bass was marginally in favour of the 800S with a slightly better extension but really marginal.
Overall the differences were so minimal that it would not cause me to trade in my HD800s for the HD800S. If I was choosing one without already having an HD800 then it would be a tricky choice and I might well go for the 800S as it offers the balanced cable at a saving.
So I am a bit surprised in one sense and yet happy in another. It does now make me think that buying a second pair of HD800s for my second system at a bargain reduced price would be a plan and to replace my current HD700s.........