I'm using the Sennheisers 650. I have some fairly high end gear. I live in a condo so I don't enjoy excellent monitoring conditions so I'm looking for the next best thing...an as accurate as possible headphone amp killer headphone amp to at least match the quality of my phones for recording and playback. I read on another board where Bob Katz recommended "Oh my goodness! In your case I would HIGHLY recommend you get a high quality combined DAC/headphone amp like the Benchmark or the Grace. Do NOT just get a headphone amp. " Anybody share his view or can recommend specific models under a grand?