I'm still a big fan of PS Audio's HCA-2 especially for what it can be had for at current used prices. It uses an analog power supply (highly desirable and has only two gain stages (no B&O Ice Modules here). It was a Stereophile Class A product when first conceived and trounced Bel Cantos effort at the time. One pro reviewer stated that many digital designs will follow the HCA-2 but they will not have the quality & effort that was afforded this amp.
To the point there is an upgrade targeted for the HCA-2 that invlolves replacing the four input caps with Black Gate capacitors. It has been mentioned in the forums that this upgrade is the most desrable & cost effective for sound improvement. I personally own a HCA-2 with this upgrade and will tell you it sounds spectacular. Extended but refined highs, a gorgeous midrange approaching tube magic and killer bass. Also this upgrade opens up the soundstage and yes I previously owned the stock unit for comparison and other new digital amps.
To the point there is an upgrade targeted for the HCA-2 that invlolves replacing the four input caps with Black Gate capacitors. It has been mentioned in the forums that this upgrade is the most desrable & cost effective for sound improvement. I personally own a HCA-2 with this upgrade and will tell you it sounds spectacular. Extended but refined highs, a gorgeous midrange approaching tube magic and killer bass. Also this upgrade opens up the soundstage and yes I previously owned the stock unit for comparison and other new digital amps.