Ok. I will add to the review at some point, but he headphones I tried included: HE-1000, Ether-C, Ether, McIntosh MHP1000, AKG 812, Focal Studio Pro, variations of the Superlux, the Telefunken Hancock, Senn HD800, Beyer Dynamic T1 Gen 1, Audeze LCD-x, Audeze Sine, Grado GH1, Dharma D1000, HE-6, Pioneer HRM-7, Yamaha MT220, Fostex TH600, Audio Zenith, and probably a few I am forgetting. I was disappointed with the HE1000. When I changed to the stock tubes, it was better, but never quite what I hoped for. I thought the HD800 was good, but I must admit, for whatever reason, I wasn't as impressed with the combo as others seem to be. I did not care for the Audeze LCD-x either. But it wasn't the amps fought. The X had a warm and less than crystal clear sound. Not bad, but not my favorite. I thought the Beyer Dynamic T1 really benefited. I think the AKG 812 scaled up extremely well. I liked the Grado, but I sensed a certain opaqueness ....hard to describe. It was good, but not great. The Dharma was pretty darn good, but that's one of my favorite headphones anyway. I also LOVED the Telefunken Hancock with the amp, but it tends to be more midrange centric and not so great on other amps. I thought the McIntosh did not go well. It's a bit bright to start with and I just didn't care for the vocals and brightness it exhibited with the Teton. The Ethers were ok, but didn't really impress me. I did like the Audio Zenith (similar to the Oppo PM1). The Beyer Dynamic DT150 also went pretty good witht he amp. Hope that helps. All in all, the T1 and the AKG 812 really stood out, along with the Telefunken Hancock (but I imagine that choice would be controversial because it isn't a megabuck headphone). I didn't listen too long, but the TH600 also sounded pretty good. I'm not a fan of a "V" shaped sound, but I think the Teton filled the mids in nicely ...still V shaped, but well controlled and pleasant. Grado 325i also sounded better than usual as the vocals were more full bodied. I was also really surprised that the HE-6 sounded respectable. Heck, I was surprised I could even turn it up loud without clipping. The HE-6 was actually a good listen, though I'm pretty sure if you primarily listen to the HE-6 you might want to try more powerful amps. Oh, I almost forgot. The HE400i and the 400s sounded pretty good. The 400s is a little anemic, as was the Audeze Sine in the bass department, but a very nice sound for those headphones, overall.