Commenting as I didn't know about this option for stereo amplification until a couple of years ago: I'm using Alientek D8, a "full digital" amplifier. It's great -- tiny, affordable, superb sound quality. Digital inputs are optical, coaxial, and USB (works as an external sound card).

To get more sources such as Chromecast, computer, and Blu-ray player I have a HDMI splitter (Portta HDMI Switch) that can extract audio from the HDMI signal before passing it forward to beamer/television.

I'm very happy with this setup.