The HiFiBerry Amp is a 100W-per channel DAC/Amplifier. It combines a DAC+ Pro and a powerful 100W-per-channel Class-D amplifier.
It will be powered by an external 12-30V power supply. It will also provide power to the Pi, no separate power supply for the Pi is needed.
It can also be equipped with the DSP add-on board to add digital signal processing capabilities. The onboard SPDIF input and output connectors will only be active with the DSP-add on board! Please consult the data sheet to understand the limitations of the TOSLink input and output.