The rDAC is a digital to analog converter. The inputs accept digital information from a source like the digital output of a CD player, transport or computer and converts it to an analog signal that your preamp or integrated amp can use.
Whether you'd want to use it depends on whether the DAC in the rDAC sounds better to you than the one that's already a part of your CD player, or if you have other digital sources you could route through it.
The manual is available for download as a PDF on the Arcam site. The power input required is 6V / 600 mA. You could probably buy a power supply from an Arcam dealer or make one up yourself with a 6V wall wart from Goodwill that supplies at least 600 mA and the proper sized coax plug from Radio Shack.
Whether you'd want to use it depends on whether the DAC in the rDAC sounds better to you than the one that's already a part of your CD player, or if you have other digital sources you could route through it.
The manual is available for download as a PDF on the Arcam site. The power input required is 6V / 600 mA. You could probably buy a power supply from an Arcam dealer or make one up yourself with a 6V wall wart from Goodwill that supplies at least 600 mA and the proper sized coax plug from Radio Shack.