As there is noise on the line during a voice call, the usual recommendation is to report that problem to your voice provider, BT. Make no mention of broadband. Once the voice problem has been fixed, see what happens to your broadband service.
The noise on the line only occurs when the router is connected, so at first glance it looks like a problem with the router or microfilter. However, I've tried two different routes and four different microfilters and the issue continues to occurs. It therefore doesn't seem to be an issue with the hardware, but that's what the BT engineer would probably blame.
Before reporting the voice fault, remove everything broadband related from the line just to ensure the issue remains.
If you don't do this an engineer will turn up and do the same test and if all is well just blame the DSL hardware and leave.
Unfortunately the issue only occurs with the DSL hardware connected, though doesn't seem to be the cause of the problem. As you say though, the BT engineer would probably blame the router, charge me £130 and not even fix the problem.
Remove the faceplate from master socket and plug into test socket behind and check.
Do you have corded non powered phone to use, cheap to purchase.
If results same, as previous post says would appear to be line fault
BT cover up to test socket only.
I've tried the master socket, and I've tried two different powered phones. However, I haven't tried a non-powered phone. I'll be going shopping on Thursday so I'll pick on up then and see if it makes a difference. Thanks for the suggestion.
The OP already disconnected everything broadband and confirmed the noise goes away. But, they have tried different filter and router and noise is the same with any broadband equipment. That should suggest an external fault but a phone engineer will probably just blame on the router/filter.
Yea, that's what I'm worried about. If I do have to call the engineer I'll show him the different microfilters, routers and phones I've tried to try and convince him that the problem is with the line, but I still suspect he'll blame my equipment and charge me the £130.
Most likely a High Resistance fault, that rectifies the ADSL radio signal down into audible noise
The change in line current during ring/calls is the big hint.
If its present with no ADSL kit present then getting fixed is easier and simpler to spot.
If present when ADSL running, then ideally need to check its not your kit and needs reporting via broadband firm and see if a HR fault note can be passed down.
HR faults usually get worse and eventually affect just the voice side too.
It's only present when I have the broadband connected at the moment. However, if it usually gets worse and effects just the voice side, I might wait until that happens so it would be easier for the BT engineer to see the problem is with the line.
The other thing I'm considering is cancelling the BT broadband subscription and BT telephone line and and going with a different provider. That way any problems should be resolved during installation. BT are terrible anyway and they keep putting up the line rental to pay for the Champions League and Premier League rights.