If you see or hear of a used CD player that you think would be good for not a lot of money, let me know.
Hi Rinpoche,
The Aeris DAC does not provide any analog inputs, so until and unless you purchase a preamp you would want to connect a digital output of the CD player to a digital input of the DAC. Or, alternatively, you could consider purchasing a CD transport, which would not include a digital-to-analog converter function and would only provide digital outputs.
It seems that in more situations than not a coaxial S/PDIF digital connection provides better sonics than a Toslink connection, although that is certainly not always the case. The Aeris provides BNC connectors for its coaxial S/PDIF inputs, while most CD players and transports (especially in the lower parts of the price spectrum) provide those signals on RCA connectors. But BNC/RCA adapters are readily available inexpensively, and can provide fine results.
Best regards,
-- Al