Yes, you can just connect five Sonos Architectural speakers to one Amp. But in stereo mode, the individual speaker that isn’t part of a pair will only play either the left or right channel of the stereo audio. You could set the Amp to Dual Mono mode, but this will send mono audio to each speaker connected to the Amp.

Thank you very much

With two on one side and three on the other you may see a volume difference, the balance setting should let you even that out.

Thanks. I’m thinking to put 2 in the master bedroom and one in the in-suite bathroom? 

That is only 3 speakers where are the other two going?

If you are installing two in two different rooms and one in the bath make sure you consider the first response to your post. Either all will be mono or the bathroom will only play the left or right channel.

Maybe two stereo pairs hooked to the Amp and add a Move or Roam (for water resistance) to the bath? 

Thank you very much Stanley. The 2 others would go in the living room

In the bathroom, install a dual stereo speaker. You’ll hear both channels, but there is only one hole in the ceiling. Use a stereo connection to AMP. The human will perceive this as a mono speaker.

You’ll need to use an impedance matching scheme. I recommend in-wall impedance matching speaker Volume controls for each speaker.

The key thing to remember is there is only a single stereo pair of posts on the Sonos Amp. You can put the entire device into mono mode if desired, but no matter what, the Sonos will always think it’s driving one pair of speakers.