Antique Sound Lab HB1 headphone amp: comments?

I am currently working on a new home construction site, and have several hours each afternoon when very little happens. I want to use the time to review some new CD's, and plan to use my Sennheiser HD-600 headphones.

I plan to buy a moderately-priced (under $300) headphone amp, and am considering the new Antique Sound Labs HB1 tube amp. I was wondering if any of our A-gon readers have had experience with this amp. Any comments that might help with my buying decision will be appreciated.
Mr. Campbell,

I can't recommend that amp, because I don't have any knowledge of it, but I do know for certain that there are very good headphone amps in that price range.

Perreaux comes to mind, as does Ray Samuels' new design, the SR-71 (I think it's $395). is chock-full of such information.

Good luck, Esfand
I just purchased one of these from Audio Advisor for $225 with free shipping. I've had it about a week and it does just what it is supposed to.

I don't have a tape out on my preamp, so I use the 2nd line-level output.

This thing is tiny, but it's as big as it needs to be.

I have one and like it. I use it with my Marantz CD player and Grado SR-60 headphones. It's a good beer budget ensemble.
I know I'm late to this thread, but I just got an HB-1 and wondered what kinds of tubes folks have used for (what they considered) the best results, and with what headphones. (I have 63ohm Sony MDR-V6's) Thanks,