Audioengine HD3's headphone DAC/Amp

I sold off my NFB-11.28 recently, and been re-engaging the audiofilét world for a new DAC and AMP desktop solution. In the meantime, I thought why not leverage the full value of my Audioengine HD3 desktop speakers and use the integrated DAC and AMP in there to drive my Sundara... Well, I'm very pleasantly surprised--to enough an extent that I thought I'd share it here since I don't think trying the headphone amp in these speakers would ever cross the minds of anyone in the hobby.

The integrated components in the HD3 are two Burr Brown chips: the PCM5102 DAC and the OPA2134 opamp, and their pairing with the Sundara is quite superb. It's immediately an obvious improvement over the NFB-11.28 (which I suppose no one in this community would be surprised about). Compared to using the HD3, the Sundara through the 11.28 sounded more aggressive, drier, and sometimes slightly harsh. Through the HD3, however, the Sundara sounds gorgeously smooth, yet just as resolving. Soundstage is a tad smaller but still quite nice, but the headspace and imaging feels a tad more coherent and precise.

The biggest differences are the liquid goodness in the upper midrange through treble that the HD3 imparts on the Sundara, and the bass. My god, the bass. The bass is incredibly satisfying through the HD3. It's wet, but not sloppy, dimensional, and effing loud. It made the bass output of the NFB-11.28 (which I had thought was its strong point) downright anemic and one dimensional.

I suppose it isn't a huge surprise that this is a good pairing. Burr Brown stuff, especially the OPA2134, tend to be dark and laid back, and Tyll evaluates the Sundara to be a neutral-cold headphone. Together, the Sundara's treble really sings like liquid diamonds in the blackness of space.