Sure. I have tried it with LCD-2 r1, LCD-3, HD 600, HD 650, D7000, T1 and some others lower end cans, all of which I currently own. Here are some initial impressions of Asus Xonar Essence One. I've not yet started changing the opamps, but sure will. I feel the value of this product is really high, and find it weird that not more head-fiers have it or are talking about it. The biggest downside is that the volume knobs are cheap and there are imbalances on the lowest settings, but you can just turn down the volume in foobar and have a greater range with lower impedance and highly sensitive cans.
I'd say HD 650 and Essence One is a very good combo. HD 650 can be a bit too smooth, laidback and lacking in details, but with the stock Essence One it is more up front, controlled and detailed in my ears. I currently own Grace Design m903 and Woo Audio WA6-SE with a ton of tubes, and that's what I'm basing the statements on. It's hard to describe sound unless you have something to compare it with.
Here is a pdf file with a step by step tutorial for swapping the opamps, and also some opamp recommendations and sound descriptions.
Thanks a lot dude. From what you're saying, looks like we have some common in term of taste with the HD 650. I'll think when the essence one is available at my country, I'll buy it. Right now I'm still using some china-made value class DAC/AMP (Topping D2, in case if you ask), and I'm still not pretty much impressed by how it sounds. The Topping D2 has made the HD 650 sounds more forward and energetic than how it normally does, but I'm still not getting the "wow" factor. I think I'll try this essense one. Thanks for the information by the way.