The new amp add-on, NanoSound MiniAmps, include both a headphone amplifier as well as a very efficient 5W speaker amplifier. It runs very cool due to its up to 90% efficiency allowing the whole unit (Raspberry Pi + NanoSound DAC + NanoSound MiniAmps) to be powered by one single microUSB cable (individually if you choose to). It's surprisingly loud and is enough to power a large room or a small lounge as demonstrated.