Sonos amp

Yes.

The sub needs to be an active sub, the Amp’s output is a standard line level subwoofer output, not a powered output.

That output does get turned off if and when you use the Amp to power surround speakers, while it is bonded to a Sonos soundbar of any type. 

Let me rephrase because i don't understand the “active” sub.I want to get a Sonos Amp and power 2 non-sonos speakers and a non sonos sub. So no power to the units., just speaker wire.

No, the Sub needs to be self powered (has its own power plug). The Sub output is, as it is on many other amplifiers, a line level output, and doesn’t power a speaker on its own.

Many Subs are ‘active’ or self powered these days. Which Sub were you considering?

Seeing the power rating of the Sonos Amp, you could run a passive Sub from its speaker terminals in addition to the speaker pair, if the room was small and bass support need therefore limited.

But there are now many active Subs for good prices that will do a better job and not burden the Sonos Amp with need for power.