Worth pointing out that the raspberry audio out has quite a bad rep quality wise:
http://raspberrypimaker.com/cheap-quality-audio-raspberry-pi...
http://raspberrypimaker.com/cheap-quality-audio-raspberry-pi...
Obviously if you're just using a cheap or old amp it won't have HDMI, but if you're amping with an A/V receiver you can just use the HDMI out and get perfectly good quality.