Subwoofer Buzz

Forums › Home Theatre (including HTPC and EPG Collector) › Subwoofer Buzz

networkn

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#243164 28-Nov-2018 20:24

Hi.

I have a lovely Monitor Audio Silver RSW12 Sub I have had for about 10 years or so. It's been pretty much flawless since I got it.

Recently it's started making a noise I can't seem to get to stop. I don't believe anything has changed in my set up.

I've attached the recording. Disconnecting the Subwoofer cable from the amp doesn't make any difference. I haven't touched any of the other switches on the back, but I have attached a photo of the settings on the back in case a kid has knocked it or something accidentally.
I also changed the power cable and power source. Turned on, with no cable for the amp plugged in, it makes the noise. Once it made this noise for like 6-8 seconds and then stopped, but when I turned it off (which makes a very loud thumping noise) and back on again a minute later, it made that noise and didn't stop.

https://soundcloud.com/networkn/subwoofer

I am assuming it may be faulty. I called the distributor today, they made mention of a board that might have failed, and that for $1000 they can replace that board with the latest version, from the current Silver Sub, and it will get "upgraded". I am not sure what difference that would make, but considering replacing this like for like would cost $2500, $1000 seems "cheap". I am hoping someone has fiddled and I won't need to spend anything.

Any assistance would be gratefully appreciated.

I have also read online this could be because of a ground loop, but I am unsure how this could now be an issue when it wasn't previously.

networkn

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#2136259 28-Nov-2018 20:26

Linux

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#2136265 28-Nov-2018 20:40

Transformer A/C buzz it sounds like could also be caused by a capacitor on the way out

John

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#2136274 28-Nov-2018 21:21

I had something similar on a Miller & Kreisel sub I had years ago. It turned out to be the gain control potentiometer that had gone. A trip to Jaycar and $4.70 and it was fixed.

Hope it turns out to be as simple on yours.

An alternative fix could be to replace the whole amplifier with a generic kit amp like in the link.

https://www.jaycar.co.nz/150wrms-sub-amplifier-module/p/AA0507

networkn

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#2136283 28-Nov-2018 21:51

Hmm interesting information, thanks.

I found this:

https://www.aliexpress.com/item/New-UK-Monitor-Audio-RXW12-Silver-subwoofers-amplifier-500W-digital-home-subwoofer-amplifier-board/32792018391.html

Which is the exact replacement board. I wonder how difficult it would be to install?

Batman

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#2136285 28-Nov-2018 21:55

When aliexpress says genuine, you don't necessarily believe it. When aliexpress says new ....

maybe it's time for an SVS

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#2136288 28-Nov-2018 22:16

Calling @dunnersfella

networkn

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#2136321 28-Nov-2018 22:22

Batman:

When aliexpress says genuine, you don't necessarily believe it. When aliexpress says new ....

maybe it's time for an SVS

Well, even those are $1800 for a 500W RMS one.

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Fred99

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#2136337 28-Nov-2018 23:41

Looks like a class D / switchmode amp.

FWIW, I had a similar fault with a bi-amped PA speaker (Class D) bought from Rockshop, and out of warranty. I was expecting serious $$$, but it arrived back fixed for $70. It was fixed by a tech workshop - not the maker's agent.
It might be worth a call to Rockshop to ask who they use, class D is common in professional sound gear, just not home hifi, someone knowledgeable servicing modern PA systems etc may be a better call than someone servicing conventional home stereo equipment.

networkn

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#2136338 28-Nov-2018 23:43

Thanks, that's excellent advice. It's not a great time of year to need to splash out 4 figures for something unexpected. My kids might end up with rocks (Coal is too expensive and my neighbour seems to have a few in his head spare lol).

richms

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#2136343 29-Nov-2018 00:03

A friend had a fancy sub that started to make all sorts of loud thumps and buzzes at random getting worse, and it was the capacitors almost all were shot in it. Not a known brand and were well down on the listed value the tech told him.

Richard rich.ms

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#2136386 29-Nov-2018 07:38

if there’s nothing connected to it , it wouldn’t be an earth loop. If you wanted to double check ,if you have a large isolating transformer you could plug it into that.

Dunnersfella

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#2136425 29-Nov-2018 09:48

If you don't have the original packaging I would think twice about sending it to Denco for servicing. Subs have a nasty habit of getting damaged corners in shipping...

Something to factor in.

If the supplier is happy to recommend someone in your area who can assess the subwoofer, that could work out. But the people who do the best work are always the people who work on them all the time.

networkn

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#2136439 29-Nov-2018 10:03

Dunnersfella:

If you don't have the original packaging I would think twice about sending it to Denco for servicing. Subs have a nasty habit of getting damaged corners in shipping...

Something to factor in.

If the supplier is happy to recommend someone in your area who can assess the subwoofer, that could work out. But the people who do the best work are always the people who work on them all the time.

Hi.

Apparently according to Denco the repair agent is in Auckland and so am I, but they declined to tell me who it was. I'd drop it off to ensure safe passage if I knew how/who/where.