The most common way is with a Sonos Port, which has an analog input for the separate receiver to feed an output to. Usually they are connected to available tape loops, but any line level output from the receiver is fine.

Some people instead choose to use a Sonos Five, which also has an analog input, although the form factor is smaller, the line in is exactly the same. 

There’s even an FAQ about it:

https://support.sonos.com/s/article/3548?

Thanks!

Can I just plug my turntable directly into the Port and bypass my receiver?

As long as the turntable is pre-amped, yes. Sonos looks for line level inputs, not phono level inputs. Receivers usually have one built in, which is why they have a specifically labeled “phono” input, which feeds that pre-amp, and sends the line level data to the rest of the device. 

To be clear, the pre-amp can be built in to the turntable, or be an external model, of which dozens of makes can be found on places like Amazon or even your local electronics store. Does not have to be “built in” at all, which you might infer from my previous post. Just needs to exist :)

Thanks - and at the same time things can still be connected to my receiver and other speakers?

Not sure I understand your question. If you connect the turntable to your Sonos directly, then you’ll have two systems, the Sonos with the turntable, and the receiver with whatever was connected to it before. The two systems would be be unconnected. 

Thanks again - Can the turntable be connected to Port and to my current receiver at the same time? So I could play albums via Sonos and two my more traditional set-up?

Not easily, no. You could just connect a line level output from your receiver, most frequently a tape out, to the analog input of the Sonos, and then get anything playing on your receiver on to the Sonos system, with one caveat….there is a small delay for buffering on the Sonos, so if you’re playing something on that receiver with its own speakers, and also sending that signal to the Sonos, the Sonos speakers will be slightly delayed from the receiver’s speakers. If they’re in another room, it’s not liable to be an issue, but could be disconcerting if the receiver’s speakers and the Sonos speakers can be heard at the same time. 

Ok thanks for all of this info - I think I would play the turntable though one or the other, not both at the same time.  I just would like to be able to switch between turntable/Sonos to turntable/receiver easily if possible.  If not I may bag my current non-Sonos speakers and get a couple of more Sonos speakers for the study…

There’s alway switches for various types of cables. You’d just need to be sure where the pre-amp goes, it’s likely the receiver wouldn’t like that.

Fairly non standard setup, I can’t think I’ve ever seen anyone else with a similar desire.

In order to connect a turntable to a SONOS Line-In you’ll need a “Phono Preamp”. This can either be built into the turntable or an external box. Receivers typically have a built-in Phono Preamp.

If you are using a Phono Preamp that is built into the turntable or an external Phono Preamp, you can use a stereo Y-cable to connect the Phono Preamp output to both the SONOS Line-In and the Receiver. You can use any input on the Receiver except “Phono”.

All of the older and some of the newest Receivers will support a cassette deck. You can use a Receiver’s “REC OUT” connected to a SONOS Line-in to send Phono to SONOS. You would set up the Receiver as if you were recording Phono on a cassette deck.

As Airgetlam notes, there will be a slight time skew between Phono output from the Receiver and Phono output from SONOS.

If your Receiver supports a cassette deck, you can connect PORT as if it is a cassette deck and send music to and from SONOS and the Receiver. Again, there will be a slight time skew.

Operationally, Line-In is simply another SONOS source and is no different than tracks from your music library or an online source. Line-In can play in any combination of SONOS Rooms.

Thanks all!