Headphone Amplifier: Burr-Brown/TI OPA2134
Interesting multi-purpose amp. Makes a point that it drives grados well in the FAQ
Just got this amp to drive a Stax SR-34 that I've had since college, but has been sitting unused in a closet for the last 15 years. Using it to listen to chamber music on an iPod in an office setting, and couldn't be happier. Perfect size and power, and aesthetically a nice match with the Stax adapter. Laid back sound, but feels great to put the old gear back to use. Almost forgot how much I enjoyed these phones.
I've been using the N-22 amp for almost a year now and it has been a very solid performer. The amplifier is very solid. It runs cools and drives my P-4 speakers to levels that can drive the family nuts. The headphone amp is also good. It pairs nicely with my Audio Technica ATH AD700s; it does a good job (but not quite as good) with my Beyer DT 880 (250 ohm) cans. All in all I've been really pleased with this set-up.
Know a guy who has these. Drive the P4s very well (they should). Sounded a bit better than my Audioengine A2s. I also wonder how the headphone amp is, the headphone amp on the D1 is really good, drives my HD600s almost as well as my Asgard 2