You say you own a “Sonos amp the older one”. There’s only been one Sonos Amp, so we’re talking about a Sonos Connect:amp? If so you cannot use it with a (non Sonos I presume) because there’s no provessing for a sub in the Connect:amp.

The sub works, it’s a Cambridge audio and works alongside the Sonos system through the amp. The problem seems to be the Rca ports not receiving sound. Just wondered if there was a trick to it. 

Or if the optical to Rca converter is the problem. Read up that people have made this work.

I’ve got the old white one, isn’t the black one the new rendition so there’s two models?

Yes, there’s two models, but they have different names. Amp (present), Connect:amp (discontinued).

Still curious about how a Connect:amp that has no settings for a sub, can play amp to a sub. Can a sub receive the complete signal and distill the lower frequencies by itself?

Mine has a sub output on the back?

You’re right. Sorry to confuse you. Both the Amp and the Connect:amp have a sub output.

A Connect:Amp is not well suited to TV use as the analog input will introduce a 75ms delay in the audio path which may drive you crazy with lip-sync issues. The Sonos devices with digital-in do not have this problem.

Thanks fir the advice guys, mainly this room is used for gaming, wouldn’t mind a delay if I could at least get it to play, it should work!