Since digital playback was in its infancy, the best sound from CDs and subsequently from SACDs has come from playing them over a two-piece system which separates the CD/SACD player into two component parts, the CD/SACD transport which reads the information on the disc and spits it out as data, and the DAC (Digital to Analog Converter) which takes the bit stream and reconstitutes it as a musical waveform. 

There are several reasons for this: First, two devices means two power supplies which results in greater efficiency in regulation.  With two devices, the magnetic field generated by the power supply of one component of the system is far enough away from the other component so as not to engender harmful EMF interaction between them.  Finally, two boxes mean more real estate for each piece which can be used to create greater distance/isolation between the power supply of one unit and the sensitive signal passing components of the other. 

Sound by Singer pioneered separate digital components back in the mid 80’s and continues to be the home of the very best digital separates from renowned companies like dCS ,Zanden,and Esoteric.