Streaming For Beginners

+1 for Bluesound Node 2i as a great place to start with the idea of stepping up to a better outboard DAC down the road if you really get into it.  But to really take advantage of it, I suggest subscribing to a good lossless streaming service like Qobuz or Tidal which stream at CD or better quality.  Node 2i retails for $550 but can be had for less.  New, used, or refurbished Node 2 or Node N100, earlier models in the Bluesound lineup which all utilize the same user friendly Blu OS user interface software would also be good places to get a start.

From looking at pictures of the rear of the Lexicon DC-2, you have available both audio RCA style analog inputs as well as digital spidif style digital inputs.  The spidif inputs make use of the DC-2's DAC, the audio RCA inputs need to make use of a DAC external to the DC-2, such as the internal DAC of a network player such as a Bluesound Node, or of a separate outboard DAC.  A Bluesound Node could be hooked up by either connection, but given that the DC-2 design is over 20 years old, it will more than likely be bested by more contemporary DACs, such as the internal DAC of a Bluesound Node.