Just to update my experiences over the last 2 days. Yesterday was the day that I dropped off my speakers, and drove home with a pair of Abyss and HD800 headphones. It was a 3 hour drive home, and I was looking forward to plugging the Abyss into my Mcintosh MHA100.
I walked through the door, and spent about 30 minutes unpacking everything, and adjusting the headband to suit. Then the moment came, plugging them in, and turning up the volume! The initial reaction was as favourable as I got during the demo, a larger scale compared to my PS1000/HD800. I sat and listened for another 3 songs, but on the last song, it didn't sound as detailed as I remebered. After unplugging the Abyss, and plugging in the HD800s, I played that same song, WOW! Suddenly all the detail and air and soundstage was back, everything was so much more musical. I compared the 2 headphones over the next 20 minutes, but I had already formed my opinion, and that is what this is, my opinion, yours may vary.
Unbelievably within 45 minutes of unpacking them, I had closed the lid on the Abyss, quite literally, they were put by the front door for returning in the morning. I spent the rest of the evening listening with the HD800, appreciating just how good they are. Now I totally understand that this could just be a mismatch of the Mcintosh/Abyss pairing, but I couldn't return them and get my speakers back quick enough. What a bargain the HD800s are, and the Abyss, well, let's just say, good riddance!