You got a set of Grados, didn't you? I find the headphone amp I built from Mapletree Audio works very well with these low impedence phones. The Ear+ design sound very close to what you described, but without the CCS. Schematics can be found in the website. I call it my personal parafeed SET amp.

Interested in hear your thoughts on the design.

Gar.

• Mapletree Audio (scroll down to Ear+ Purist)