I own the NuPrime HPA-9 and it's a great headphone amp. The tone is slightly to the warm side, but only slightly. My old amp was the headphone out of a NAD 3020B with the preamp bypassed and it was warmer than the NuPrime, so I may be jaded. Presentation is a little bit more forward than the NAD, detail is fabulous, headstage is good, dynamics are forceful, bass is tight and deep, treble sweet and clear. There's three headphone outs, two 1/4" and one 3.5mm, a decent phono stage if you ever add a turntable, a high/low variable gain, and a couple of RCA inputs and outputs if you ever want to use it as a preamp. My only bitch won't matter to you, when used as a preamp it doesn't mute the RCA out when you plug in a headphone. I haven't had anything I like better including Woo, ZOTL, or Schitt.