About the question that asked if the m902 could handle the output from "DVD-Video, SA-CD, DVD-Audio, and Red Book CD (along with HDCD or JVC xRCD)"
My feeling, and this is just an educated guess, is that the Grace units (901/902) will only be able to digitally decode the audio in some of those situations.
DVD-Video (well the digital audio stream)
- I think this is likely only going to work if you aren't outputting any fancy DTS/Dolby surround-sound, downmixing 5.1 --> 2.0 or something.
Generally I think one can forget about multi-channel audio - these DAC's are not designed to decode this stuff, presumably that requires additional hardware or licensing fees to be paid to Dolby Labs or whoever. Plus even if they could handle it, they don't have multi-channel outputs, so you'd just have to throw that data away. It would be nice if they could "pass-thru" the data say on to your high-end surround sound processor, but they don't seem to have a digital out. Some models do, but even then I doubt you'll find that they support that.
SA-CD (digital audio stream)
- assuming you can GET your SACD to output its contents digitally, without downgrading the bit-rate, I'm not sure that this would work. SACD doesn't use PCM encoding, but rather DSD (iirc)
DVD-Audio (digital audio stream)
- this should work, since DVD-A is just PCM-encoded but using higher bit-rates, and the Grace supports up to ... 192 in the m902. The m901 supports up to 96. I am not sure if there is a standard bit-rate for DVD_Audio, it seemed it was kind of up to whoever masters it.
Red-Book Audio CD
- yeah this should be fine, plain-jane CD audio right...
HDCD
- this would require some additional firmware or decoder hardware, and I doubt that this would be supported by the Grace or any DAC that does not explicitly make that claim. I think Microsoft now owns this code/algorithm anyway, they bought the company that previously held the patent on it, iirc.
xRCD
- wow I must have missed that one ... never heard of it. If it requires any similar decoding like HDCD, probably not supported.
Anyway, this is just my theorizing, if someone else knows better then feel free to correct me. I'd love to find out that some of the stuff above IS supported.