I've had my HD600 for about a year. While I enjoyed many of the positives discussed in this thread, I didn't love the cans. Liked them a lot, but that last bit of satisfaction was lacking. Most of the time I drove them with a Vio V200, and sometimes with a Corda Concerto. Neither combo really did it for me. It felt like the cans were almost stuck to the head, sonically, with limited staging abilities. Then, a couple of months back, I picked up another Little Dot mkIII. I had one before and didn't really care for it, but the offer included a number of tube choices and a price that was hard to refuse. To make a long story much shorter, I absolutely love - no, loooove - the LDIII/HD600 combo. While I still prefer the other amplifiers with most of my HPs, the HD600 now only see tubes. The staging issue is gone, the cans have more life to them without sounding etched or exaggerated. It's as if I got a new set of truly superb headphones. Listening to the combo at this very moment playing a HD file. Stunning sound quality.