Buzzing in Speakers

Pandoran

Novice Member
Hi everybody, I apologise for the long post but I thought it would be best to be thorough and give you as much information as I can think of right away.

My issue is I'm getting buzzing and humming sounds coming from all 5 of my speakers

I suppose I better start with my setup, I'm equipped with a Sony STR-DG820 amplifier hooked up to 5 Focal Sib and a Cub 2, all of which were bought at the same time about 10 years ago.

The whole installation consists of the amplifier, the speakers, a PS4, an internet TV box and of course the TV, I've also got the router and the landline phone plugged in next to all of this.

I'm encountering two different noises through the speakers, the first is a low hum which is present at all times as soon as the amplifier is turned on, the second noise is a higher pitched buzzing which only appears when media is playing. If I pause or mute it at the source (e.g : muting the TV) this noise disappears, the same thing happens in that brief moment where the sound cuts out when changing channels. Muting or lowering the volume of the amplifier does not stop or change the volume of the buzzing.

At the moment the TV box and the PS4 are connected to the TV through HDMI with an optical cable going from the TV to the amplifier. I've tried plugging everything straight into the amplifier using HDMI and then connecting the amp to the TV with HDMI and that seems to reduce the high pitched buzzing noise but seeing as the amp is quite old that means bye bye any output over 1080p and HDR

I'd been running a 3.1 setup for the past few months until I got around yesterday to buying new cable (2.5mm OFC) and setting up the last two speakers as well as rewiring the previous ones.

The low hum was already present and bearable in the previous setup but seemingly a bit quieter, though I don't know if that's just because of the two extra speakers plus the fact everything is now better set up with a less obstructed sound path.

The new buzzing sound however is just nerve-wracking, it's just loud enough to really mess up those quiet moments in movies and games. This sound also seems to disappear completely once the speakers start outputting a high enough volume

The cable lengths between my speakers are approximately:

15m
9m
9m
5m
1m

Everything is of course wired up correctly.

I've looked up what could be the source of the issue and the frequent problems seem to be grounding loops, interference from AC cables and a worn out capacitor

I've tried plugging speakers back in one by one but the buzz appears as soon as I've plugged in the first one, I've grouped all appliances on to a single power strip but still no change, I've made sure the audio cables aren't tangled up with the power cords and are all to one side.

I read that it's best to avoid running audio cables parallel to AC lines, which I couldn't avoid but there are about 10cm between the two

Just before plugging everything back in I took the chance to clean inside the amp with a can of compressed air and noticed some heat markings on the sides of the amp cover.

I'm also attaching two recordings, one of the first low hum and one of the second higher pitched buzz as well as photos of the inside of the amp, the casing, and my cable installation in hopes that they might help you identify the problem.



Low hum:
Domicile-2

Buzz:
Domicile

Amp casing:
IMG_5818.jpgIMG_5816.jpg

Inside of amp:
IMG_5812.jpg IMG_5813.jpg IMG_5814.jpg IMG_5815.jpg

Cable installation:
IMG_5808.jpg IMG_5810.jpg

General Setup:
IMG_5809.jpg


Thanks already for reading the long post and for any help you can give me, I hope I can find a solution even if it means repairing or replacing the amplifier.
 

Attachments

  • Domicile.mp3
    146 KB · Views: 34

dobrykamil

Well-known Member
Hi
Based on my experience, any buzzing on Sony av receiver were caused by dodgy capacitors in +7 and -7V circuit for volume/input selector - in your case it's IC400. Since the buzzing stops when you mute the source, I would look at the DSP section, although the buzzing sounds like bad filtered DC.What about the analogue inputs in Direct mode?
 

Mark.Yudkin

Distinguished Member
I'm going to assume its not a hardware defect but a classical ground loop (hum), PC noise (buzz).

Lets' start with the hum. Disconnect all source devices from their signal feeds - that is internet, phone, landline, router, cable TV, satellite TV, aerial. Also completely disconnect any (media) PC, laptop, Mac or similar devices from everything, everywhere. If feasible, hide these devices under the bed :).

You should now be unable to watch or listen to anything (except perhaps a CD or LP), but should also have no hum (and no buzz). If you do have issues, work out what's broken and get it serviced. Otherwise slowly reconnect until you have issues and report back.
 

Pandoran

Novice Member
Already done all that, Buzz still comes back as soon as I plug in the first speaker with nothing else close by (I set up the amp and speakers before setting up the rest).
 

Pandoran

Novice Member
Just had a look at the photos and realised that I've connected my rear speakers into surround back instead of surround :thumbsdow.
Switched them around but as expected it still buzzes.
 

Mark.Yudkin

Distinguished Member
Already done all that, Buzz still comes back as soon as I plug in the first speaker with nothing else close by (I set up the amp and speakers before setting up the rest).
Just to confirm your prior statement by being precise: A system with just the amplifier and the passive speakers (i.e. without the subwoofer), but with no sources connected in any manner, buzzes, but doesn't hum?
If so: 1) the amplifier needs servicing as it's broken and 2) the hum is a different issue, but you might as well wait until the amplifier is repaired before trying to track down the hum.
 

Pandoran

Novice Member
Just to confirm your prior statement by being precise: A system with just the amplifier and the passive speakers (i.e. without the subwoofer), but with no sources connected in any manner, buzzes, but doesn't hum?
If so: 1) the amplifier needs servicing as it's broken and 2) the hum is a different issue, but you might as well wait until the amplifier is repaired before trying to track down the hum.

Sorry about that I answered in a hurry and I wasn't very clear, with nothing else connected and plugging speakers back in one by one I just get the hum, the buzz on the other hand only appears when there is an unmuted audio input no matter what that input is (PS4,TV, etc...).

Having been using my setup anyway despite the buzz, I've also got the impression that the buzz is more audible when watching TV compared to playing games or watching Netflix, But that may just be related to the fact that these sources emit a higher quality audio track that does a better job of covering the noise.
 

Mark.Yudkin

Distinguished Member
The buzz may well be caused by a connected "computer" component, but you have a hum, and you I therefore strongly recommend you start by addressing the fault you have localized.

Since it occurs even though the Focal Cub2 and all other powered components are disconnected, and the level is above the level considered normal for your Sony STR-DG820 (else you wouldn't be mentioning it), the first thing to do is get the STR-DG820 serviced. You can then see if that helps with the other symptoms, if not we look for a second issue.

Incidentally, a high quality audio track will not affect the level of a buzz, it is only volume that can cover up low level noises.
 

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