A very quick first impression. MacBook Pro running Fidelia>Explorer>Toxic Cables silver widow 3.5 jack to twin RCA > Icon Audio HP8 Mk2> HD800
Set up a simple plug and play, no problems at all. I just had to adjust the Fidelia setting to the correct output - Meridian Explorer rather than built in and I got music straight away.
Sound initially clean, very detailed, slightly lean, top end a tad over emphasized and bright, sound stage a little compressed. I left it to run for a couple of hours.
Now I still notice the detail first but the overall balance is much more satisfactory, even after just a couple of hours, with the bottom end filled out more and the upper range toned down closer to what I'd expect to hear. Very dynamic and transparent presentation with a well defined, wide-ish sound stage and plenty of air around the instruments. Vivid and neutral are the words that comes to mind, there's nothing veiled or laid back at all about what I'm hearing, but all seems to be well controlled right across the sound spectrum. It's a bold presentation of the music - exciting - with very good dynamics and a very real sense of the instruments being played and, more importantly the way they're being played.
With more subtle, gentle music things are still good - very euphonic. Human voices are nicely presented. Very impressive with electronic music too. The combination with my tube amp seems very promising indeed. I can't imagine anyone being disappointed with what I'm hearing at the moment and, who know, it may well get better....