I recently swapped my possibly faulty hh6 for a hh3 and a open reach modem made by Huawei.
Before i swapped it, a quiet line test would be mostly quiet apart from a very faint hissing sound; it was that quiet you needed to put your ear right up to the ear peace, block the mic and be in a quiet room. Now I've plugged in the openreach modem i am now hearing a slight buzzing noise, no crackling, just a buzzing noise. Could this develop into an even bigger fault? Will this affect my broadband by reducing speed or/and causing it to cut out? Im thinking that the open reach modem might be throwing the buzzing back onto the line as the said buzzing has seemed to coincide with me swapping the equipment.
My current setup is a telephone extension running from the master socket into the extension socket where the micro filter is plugged in and finally the dsl lead to the modem.
For anyone wondering the fault on the hh6, it kept restarting and dropping BB connection for no apparent reason.
Im thinking of moving the modem to the master socket downstairs and re-use the cat 5e telephone extension as a normal Ethernet cable
A quiet line test should be silent with a corded phone, not mostly quiet.
as already said by @pippincp any noise on quiet line test is a problem for broadband - so even almost quiet is a problem and needs fixed
it could easily be the result of the extension wiring from master to extension socket and then connecting filter and hub
try just connecting filter to test socket an see if that still is 'almost quiet' and if so report phone fault to 151
With the quiet line test there is no such thing as significantly quiet. It is either silent or it is not.
With that I will bow out of this thread as you are obviously not listening.
My first thought without access to diagnostics is an earth problem. I would also be tempted to disconnect terminal three on your master socket (on the removable faceplate). This is the ring wire which tend not to be required these days, but has a history of causing 'noise' on your internal cabling which can affect broadband and sometimes voice.
Good luck!