Sonos Connect and Sonos Connect: Amp is both new names for two of Sonos's products, i.e., The ZonePlayer 90 and the ZonePlayer 120. Sonos had recently made a few changes in its products, and this has also led to the renaming of some of their products.
Sonos Connect, which is now a new name for ZonePlayer 90, when connected to a home theatre, can be used to play different kinds of songs, and can also be used to stream music to any audio device. Sonos Connect can also be used to control your speakers even when they are positioned differently inside your home.
You can also use the Sonos Connect app to stream music on any device that supports it. On the other hand, Sonos Connect: Amp also has similar features like Sonos Connect. However, one of the major differences between Sonos Connect and Sonos Connect: Amp is that the latter comes with a 55 Watt power per channel integrated amplifier, whereas the former does not.