Beolab 4000 are active speakers with integrated amp.

All you need is surce, preamp, or like.

Buying the Connect would be a better option. use RCA out of Connect to RCA in on Beolab 4000.

Speakers will go into standby after a loss of signal after a short while.

Hi kai,

You can use the Sonos Connect:Amp with the Beolab 4000 speakers, but as mentioned above, the cheaper Sonos Connect is the better option, as Beolab speakers already have amplifiers built in.

Using the Connect:Amp unit also requires a special Attenuated Converter ( link ) for the Connect:Amp unit, as well as the cable listed below, to reduce the amplified outputs of the Connect:Amp to safe levels for the Beolab speakers to accept.

For either version of Sonos unit, you will then need one set of the following cables for each pair of Beolab 4000 mk.1speakers to be connected:-

That's supposed to be humor, right?

Edit: Try to be helpful...  OK.  @kai, if @elephant wasn't trying to be funny, it's still a joke: No, you should not buy a Core.  No no no no no.  Well, at least not unless you have a B&O multi-room setup going.  Yes, you should swap to a Sonos Connect.  You can tell from your use of their application, how convenient it is.  If money is an issue (e.g. buying used BL4000's), a pre-owned ZonePlayer 80 still works fine with the current software too.  I have never had to "occasionally" re-boot my Sonos system.  (Well, they are a little fascist about forcing updates on you, but otherwise never.)