What is the context of your question? In other words, are you asking what is the best way to connect a CDSD to a DCC2? If so, one would get the required three proprietary cables with his/her purchase from EMM Labs. You can visit their website, download the manual, and see exactly how to connect the two units. The diagram is color coded and idiot proof.
Or, are you asking what is the best way to connect the DCC2 to another preamp, using the DCC2 as a two channel DAC only? If so, then one would use balanced XLR cables to connect the DCC2 to the preamp. Even in this context, however, one still would use the three proprietary cables to connect the CDSD to the DCC2.
Or, are you asking what is the best way to connect the DCC2 to another preamp, using the DCC2 as a two channel DAC only? If so, then one would use balanced XLR cables to connect the DCC2 to the preamp. Even in this context, however, one still would use the three proprietary cables to connect the CDSD to the DCC2.