This Itek device has no outputs (RCA line out) on it at all? That’s super odd, and shortsighted by them, in my opinion.

But yes, you can potentially use a headphone jack. It’s problematic, as you’re then fighting with two volumes, the one for the headphone output, and the one for the Sonos line in sensitivity. If you’re forced to use this, I’d start my attempt with the headphone volume somewhere around 40 to 50%, so that a good signal can be recognized by the Sonos…and then never touch that headphone volume again, once you have made the connection. 
 

That's great Bruce thank you.  I assume I need to buy one of those sonos line in adapters and a headphone cable.  I will give it a go and see how it works. If it doesn't then it gives me an excuse to treat myself to a new turntable. 

I’ve not purchased a cable recently, just make sure you have the correct connection types at both ends. 

I do have a memory of driving to multiple Radio Shacks to find what I needed, before Circuit City and then Best Buy were ‘big’. These days, I’d likely go to Amazon, since I’m no longer close to a Fry’s (which may have gone out of business)

@Airgetlam 

OK...you went to Radio Shack and Circuit City which are both defunct...so let’s jump into the WayBack Time Machine and visit my favorite the HeathKit. 

I just couldn’t close the door on your comment regarding Radio Shack (aka Tandy Corporation at one time) and Circuit City

You guys did Radio Shack and CC, whereas we in the Boston area had this mecca:

https://www.youdoitelectronics.com/

It was like Disney World for geeks.  I used to spend entire days there.  When that store closed, it was like losing a piece of my childhood. 

I remember my father made a Heathkit color TV when we returned from Europe, and we watched the moon landing on it. It had a wired remote . 

And yes, I’m old!

That goes for both of us being Old. Who on earth would remember a HeathKit except people like us. 

My family didn’t get color TV until 1972.  I ran home (4 whole blocks) from 2nd grade at lunch just to see it.  I was in awe. 

Just to close the loop, @Beatlepaul66 is in the UK, so Tandy was the shop back then (the UK name for Radio Shack). Alternative would be Maplins - also now pretty much defunct! 
 

Hmmm, the post with just text gets moderated, the one with the link goes right through.  Way to go, Gainsight. 

OK...since we’re rocking nostalgia here’s a brain teaser (and no fair googling the answer).

What electronics company had the patented catchphrase (slogan)...”The Quality Goes In, Before The Name Goes On”