Musical Fidelity V-Can Headphone Amp

I am interested in hearing from anyone who may have this inexpensive headphone amp. It is connected to my Krell amp with a set of Kimber Silver Streaks and am listening with Sennheiser D600's. At first, the unit sounded like a fork scratching a plate, after about 24 hours it calmed down quite bit, but after another 24 hours, no additional improvement. The sound is what I would call accurate, but it just seems like I'm listening to a "tin can quality". I know I could spend a lot more but I do not see myself using it very frequently, however, I would welcome any suggestions on how to get the best of this beast. I was told in three months they are coming out with a better power supply than the wall wart.
Thanks!