There are some tiny USB sound cards these days! (Not sure if the quality meets the requirements though.) http://plugable.com/2014/09/23/plugable-usb-external-a

There are some tiny USB sound cards these days! (Not sure if the quality meets the requirements though.) http://plugable.com/2014/09/23/plugable-usb-external-audio-windows-mac-linux-chromebook http://plugable.com/2014/09/23/plugable-usb-external-audio-w... http://www.audioquest.com/usb_digital_analog_converter/dragonfly-dac http://www.audioquest.com/usb_digital_analog_converter/drago...