I haven't run powerline systems for hi-fi for some while now, but a couple of days ago I had a rethink about the connection of our TV to the router. For boring reasons to do with being close to the North Pole, getting regular TV signals via an aerial is almost impossible, and satellite reception works, but is not always convenient. I would like to get the satellite system working better, but that would require more wiring, so I've not pursued that too vigorously. It's still a possible project, but not urgent, nor immediate.
I did in the end connect the TV with a powerline link, and some of the problems of the TV have now largely disappeared. Since reconnecting with the powerline link, the buffering which was a problem before - with an Amazon Fire HD wireless link, appears to have gone. Additionally, the lip sync issues which we noticed after running TV for a while also seem to have gone.
I have only played one CD since doing this, and I can't in honesty say I listened closely enough to detect the presence of the interference from the powerline system. I suppose if I were really bothered I could disconnect it when I wanted to listen to music rather than watch TV.
I'm not saying there's absolutely no interference, but simply that for practical purposes sometimes powerline systems have their uses. I also took the opportunity of reconfiguring the system to check out the operation of another powerline link - a repeater, which has a wireless access point at one end and a powerline unit at the other. I was not sure how this operated before, as TP-link suggest it's plug and play, but don't say how it works. However, as far as I can see, the extension really is via the powerline, not via wireless (like a wireless repeater) - tested by disconnecting one end of the link and waiting to see if it would reconnect via a wireless link. It didn't. That system was based on this -
https://www.amazon.co.uk/TL-WPA4220K...s%2C167&sr=8-6 for use with a TV which doesn't have an ethernet connection.
The link to the 49 inch 4k TV is via two powerline adapters back to back - as that TV does have an ethernet socket.