I can confirm that the Vali is very, very nice with HD800s. I am using the Odac with these. Compared to the O2 amp these are a big step up in smoothness and expansiveness, while avoiding any loss of clarity (i.e. stereotypical tube muddiness) or obvious emphasis in any region. Some tracks that gave me problems with the 800s seem to be a lot more listenable. I might just be lucky, but the microphonics seem very hard to trigger on my unit. I am running my HD800s stock right now, but I hear this amp sounds great with the Anax mod. I give it a very confident two thumbs up, at least with the HD800.
"Ditto" on the excellent sound with the HD800s! I found a decent cable to go between my DX100's 1/8" Line-Out and the Vali and have been taking a listen. BTW my HD800s have the Anax mod.
I'm playing some tracks from Stevie Ray Vaughan's Texas Flood (Mobile Fidelity's remastered). The bass slam of Tommy Shannon's guitar is clean without blurring of the notes, and every other range is smooth right up through the treble. It might be expectation bias, but the sound stage seems a bit wider through the Vali than directly from the DX100's headphones output.
Microphonics are minimal and fully disappear within 5-10 seconds, even with the Vali sitting right on a hard shelf surface (on rubber feet attached yet). I tried a lower impedance set of cans (modded JVC HA-S500) and microphonics, while much more pronounced, were gone in about 20 seconds. All in all, it's not really a problem.
If the Vali sounds this good right out of the box, I can't wait for burn-in to commence.
Edited by 4nradio - 11/29/13 at 8:08pm