No.  See here: https://support.sonos.com/en-us/article/surround-sound-guidelines-and-limitations

• Era 300

¹Era 300 can be used as surround speakers for an Arc or Beam (Gen 2) only.

But how about Era 100 as surrounds for Amp - can’t seem to find anything conclusive about that.

Not sure I understand the question.

Under the label:

Sonos products that can be used as surround speakers

there’s the listing for the Era 100. 

I think you may be confused by the fact that the Era 300 includes more “channels” than the Era 100. Think of the Era 100 as just a slightly larger Sonos One. It doesn’t include the same height speakers/channels as the Era 300. 

Yes. Era 100 can be used as surrounds with an Amp (Confirmed under the Era 300 Announcement thread)

It is confusing as only Era 100 can be used with Amp or Beam (Gen 1), and neither Era model can be used with Playbar or Playbase.

thanks Mr T I saw the confirmation hidden in the announcement thread on Era 300  Now they just need to update the FAQ where they state it is only compatibke with Arc Beam and Ray as you also spotted

Two tweeters, larger woofer.

Hello 

I have exactly the same question. I wondered why we can use era300 only with sonos arc and beam2 and not with sonos amp so I called yesterday the sonos hotline. The answer was : 2 drivers are missing on sonos amp.

I am not really sure that is a physically  limitation and not a software limitation... but it was the official answer.

If you have other information about it, I am interestead.

I find it really unfortunate that the sonos era300 are not compatible with the Sonos amp!

Why? The only extra you get on the 300’s is Atmos, which the Amp is not capable of. If you want bigger speakers you could buy a couple of Five’s.

Yet another reason the Amp is badly in need of an update.  Anyone who want Atmos, which is most home theater people these days, can forget about the Sonos Amp.

That would mean the new Amp would nee to have the possibility to drive more passive speakers - so more wires, which is not Sonos’ USP. Or Sonos would need to add the possibility to use wireless speakers as front Atmos speakers - only for the Amp because both Beam and Arc are Atmos capable themselves. I’d be surprised by Sonos going this way (but I’ve been surprised before).

Still holding out hopes for using a Sonos Ray as center channel for my Amp + passives + Play 1s and Sub Gen 3 setup :)

And the perhaps having the ERA 300s as surround for Atmos? :)

Would love to be able to use a Sonos Amp to power my Klipsch R-800F speakers as front mains, then use a couple of Era 300 as rears. Even better, be able to add a Beam or a Era 300 as a centre speaker. 

I’m over simplifying, but its just software really. Anything should be possible with an update from Sonos. 

This drives me flippn mental!!!! SONOSSSS!!!!

I just went to RicherSounds to demo the ERA 100 vs ERA 300 - the 300 sounds a lot clearer than the 100; it is NOT just about ATMOS

So I asked RS if they would work as rears with my new SONOS AMP (that has nice Monitor Audio Gold 200 as front speakers) and they said yes!

SONOS have some very stupid limitations with their products and frustrate the hell out of me - I don’t care if it doesn’t play true ATMOS, at least allow the surround signal to get to them if users want it do to (this is clearly a software restriction because they can play normal stereo like the ERA 100 and ONE series)!

I know I’m going to get fanboy responses, but this is how I feel…starting to get fed up with SONOS and going to go back to Receivers

I bought two for my birthday, now I have to return them!!!!! Very frustrating, again