8800NL - high pitched noise

[jrawle]

Would it be possible for me to purchase a new power adapter from Billion? Is this a service you offer?

I can't have the router / adapter exchanged as I can't be without my internet connection for a period. Also, I can't carry out the extensive tests I would with any other equipment because every disconnection risks having my line speed capped by Openreach. (I already had my speed capped, and it took 12 days' continuous uptime to get it removed. Apparently, this can be up to 56 days in some circumstances!)

So please it is possible for me to have a new power supply - I'll pay for it - direct from Billion so that I know it's the current type and not old stock? Then I can switch it over once, and it either solves the problem or not.

[billion_fan]

Would it be possible for me to purchase a new power adapter from Billion? Is this a service you offer?

I can't have the router / adapter exchanged as I can't be without my internet connection for a period. Also, I can't carry out the extensive tests I would with any other equipment because every disconnection risks having my line speed capped by Openreach. (I already had my speed capped, and it took 12 days' continuous uptime to get it removed. Apparently, this can be up to 56 days in some circumstances!)

So please it is possible for me to have a new power supply - I'll pay for it - direct from Billion so that I know it's the current type and not old stock? Then I can switch it over once, and it either solves the problem or not.

PM sent

[gatekeeper]

If a replacement power-brick does solve your problem, can you post back here please, so that the rest of us can know? I'm keeping my fingers crossed for you.

[jrawle]

billion_fan very kindly sent me a replacement power supply. I plugged it in this morning, but unfortunately the noise is still there just the same as before.

As far as I am concerned, this closes the issue. Over the last couple of weeks, I haven't been bothered by the sound in real life circumstances. I have to listen out for it or stick my head under my desk where it sits to hear it. I guess it's a "feature" of this modem, but few people will notice it as the room has to be very quiet (plus some people's hearing may be less sensitive at the high end).

Overall, I'm quite happy with the 8800NL. After reconnecting, my speed has crept up further. I have a better speed than I ever had with the BT/Openreach kit.

[gatekeeper]

Are you still convinced the noise comes from the 8800 itself, rather than from the power-brick?

[jrawle]

Are you still convinced the noise comes from the 8800 itself, rather than from the power-brick?

Absolutely. They are separated by the full length of the power cable. I have to get up close to the modem to hear it, unless the room is very quiet. The sound comes out of the ventilation holes in the top and back, so it more noticeable from behind the modem.

I think I need to find a way of taking a screenshot from bs-spectrum on my phone to prove to people the modem is making a sound!

However, as I said, it isn't bothering me now I'm satisfied it's not a fault with my particular unit, so I'm happy to let it rest.

[gatekeeper]

Given what you've discovered, perhaps billion_fan could report this to the Billion hardware developers, as presumably it's some sort of electro-acoustic resonance? A device such as the 8800 should not be producing that.

I suspect that because the 8800NL was sold comparatively cheaply, some corners were cut in its design and/or factory production.

I have it in mind to get myself an 8900AX-2400, to replace my own 8800NL (only used thus far in ADSL mode), just as soon as Billion sort out the rather fundamental problems encountered with the initial release of the 8900AX. But if I find that the 8900AX makes a high-frequency noise all the time - and as I mentioned before, I've got good ears - it'll go straight back and I'll ask for my money back. With the 8900AX costing over £230, it should be near-perfect and not doubling as an audible irritant. No modem-router should, whether VDSL or otherwise!

[jrawle]

If anyone is interested, here is a frequency spectrum showing the noise the 8800NL makes. I finally found a way to screenshot what is on my phone without disturbing it or making a sound (please excuse the "superuser" message overlayed...)

The bottom plot was with the phone sitting on top of the 8800NL. A spike around 8 kHz is clearly visible. For comparison, the top plot was with the phone sitting on the same shelf about 50cm from the modem. The background is broadly the same (and not easy to get a clean recording as passing cars affected the measurements!) The 8 kHz spike is visible in any spectrum measured with the phone on top of the modem, though.

noise.jpg

[mognog]

Have you tried moving your router to a new location just in case it's some sort of interference (a bit like having as mobile phone near a speaker). Worth a try.

[jrawle]

Have you tried moving your router to a new location just in case it's some sort of interference (a bit like having as mobile phone near a speaker). Worth a try.

It was initially in a different location as I needed to buy a longer cable. The sound was more noticeable then due to its location. Now it's less of a problem.

I somehow doubt it's any sort of external interference as the noise only starts when it makes a VDSL connection. In fact, I feel there is slight modulation of the sound in sync with the flashing of the internet light.

But really it's clutching at straws. Unfortunately, some electronics just make a noise. The BT Home Hub 5 is absolutely dreadful. It would be interesting to see the result of other people running a spectrum analyser on their phones, though.