Per your inquiry, I am using the USB output. With a Mac (or any computer based server) you would want to AVOID SPDIF type of outputs whenever possible! SPDIF (both optical and electrical) are an "ugly tangled mess" of the clock and the digital music data. The sonic benefits of using a properly designed DAC to a Mac (via USB for instance) is many fold and can offer a HUGE jump sonically compared to anything SPDIF connected. Fro instance, Jitter alone can be reduced or eliminated in up to half a dozen areas with the USB implementation as compared to SPDIF implementations.
The D/A converters I use in my various audio systems are all from UltraFi Audio Designs.
The D/A converters I use in my various audio systems are all from UltraFi Audio Designs.