We absolutely need two things:
A decent audio chipset, and an internal SPDIF header on the motherboard. The latter is being replaced by RGB headers for real estate. Motherboards do have SPDIF out, but these are generally garbage optical ports, and no good in high end systems. We take the SPDIF header's output and use a proprietary daughterboard to electrically isolate the digital signal, boost its voltage, and decrease the rise time to produce a stunning digital stereo source (multiple annual awards from The Absolute Sound, Stereophile and other publications). This is then output as a 110 OHM AES/EBU signal, or a 75 Ohm coaxial BNC SPDIF.
The 1220 chip is very nice after the signal has been cleaned up and denoised by our daughterboard. The older 892 chip is even lovelier, especially for those who prefer a warmer "analog" sound. Going forward, it seems the 887 chip is the one that continues to offer a SPDIF header, and so far it's playing nice with our daughterboard, and may end up as our best sounding base system. My company is called Baetis Audio; it was based in Montana, and I worked for them remotely, but I took over the company and brought it to Montreal 3 years ago.