I have been using SL-G700 SACD directly feeding the SU-G700 (original) via coax digital out which I prefer over analog out. I have found Direct digital out has a "quicker" sound, less processed sounding, though analog out sounds "warmer". Of course, when listening to SACDs, one has to use analog out.
This is a quote from the Peachtree GaN 1 Beta thread:
The GaN 1 is also designed so that it does NOT require a digital-to-analog-converter (DAC). The digital audio signal at the input directs the amplifier outputs to drive the speakers. Although DACs have continued to improve over the years, there is no DAC better than NO DAC!