Called OPPO today regarding the hiss and my SE846...
Unfortunately, I was informed that they have determined the HA-2 will hiss with the SE846... But whether or not you hear it does in fact come down to individual ears. I'll be damned, sounded very loud to me. But then again, I've been accused of having bat ears.
At any rate, OPPO has terrific customer service, they were very cool about issuing me a return label, no hassles at all.
I'm bummed. It's a terrific little portable unit which I think has a fantastic sound when used with full-size cans and higher impedance IEMs. And one of the sexiest form-factors I've ever seen... It matched so well with my iPod Touch 5g silver/black, right down to the chamfered polished edges. But I'm looking for something for on-the-go with the SE846, so back it goes.
Pie-in-the-sky thinking, but how cool would a mid-product run update be, with sensitivity settings for IEMs, like the IFI Micro iDSD... What do you think, OPPO? Maybe an HA-2.2 next year? I'd be all over that!