Heck if you're ready to spend $2500, why not check out the Red Wine Audio Isabella? I've heard the Signature 30.2 integrated amp, and while it doesn't sound super powerful in loudspeaker systems, I'm sure the Isabella would have plenty of power for a set of headphones. The quality of sound produced by the 30.2 is similar to tubes, but without distortion. It's like silk smooth solid state performance, loads of detail.