AVR buzz/hum - what can be done

A

avesatani

Enthusiast
Hello all !

Hopefully this will not be my only post here :)

I'm having a trouble with my home theater setup. Recently i've noticed a buzz/hum ( really i can't tell the difference ) coming from the speakers.
Here is the setup:
Yamaha RX-V377
2x Boston Acoustics cs 260 ii
Samsung LED 48" ( kill me i don't know exact model, but i think it's irrelevant )
HTPC with Nvidia 1060 GPU

HTPC is connected to AVR with HDMI, then AVR is connected to TV with HDMI on ARC port.
The setup is used for music/movies/gaminig/Youtube.

I've tried to troubleshoot the problem with disconnecting anything from AVR and leaving only the speakers, but no luck.
Tried connecting AVR to various different power sockets, still buzzing.
Tried connecting AVR to UPS, nothing, still buzzing.
When i mute the volume on AVR, the buzz is still there, changing the volume doesn't change the buzz strength.
Unplugged the ISP router, no change, still buzz. I even did unplug the fridge, no luck !
Tried all sources, all DSP programs, nothing changes.
The only thing that did lower the buzz is lowering the AVR display brightness to minimum which makes the buzz acceptable.

So the current situation is, buzz can be heard only if one is near the speakers.
Any sound that is played from HTPC HDMI source mostly or totally covers the buzz, like music from MusicBee or any video from Youtube or VLC player, except the FM radio.
The volume on FM source is really low and the buzz is here louder then on HDMI from HTPC and i have to turn the volume up to cover the buzz.

Is this the AVR crying to be replaced or are the speakers ?

Thanks in advance !
 
V

VMPS-TIII

Audioholic General
If your receiver is under warranty I would contact the manufacturer for guidance. When the buzz is higher based on the display illumination that would be a clue. Passive speakers don't buzz. It's always something downstream.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Hello all !

Hopefully this will not be my only post here :)

I'm having a trouble with my home theater setup. Recently i've noticed a buzz/hum ( really i can't tell the difference ) coming from the speakers.
Here is the setup:
Yamaha RX-V377
2x Boston Acoustics cs 260 ii
Samsung LED 48" ( kill me i don't know exact model, but i think it's irrelevant )
HTPC with Nvidia 1060 GPU

HTPC is connected to AVR with HDMI, then AVR is connected to TV with HDMI on ARC port.
The setup is used for music/movies/gaminig/Youtube.

I've tried to troubleshoot the problem with disconnecting anything from AVR and leaving only the speakers, but no luck.
Tried connecting AVR to various different power sockets, still buzzing.
Tried connecting AVR to UPS, nothing, still buzzing.
When i mute the volume on AVR, the buzz is still there, changing the volume doesn't change the buzz strength.
Unplugged the ISP router, no change, still buzz. I even did unplug the fridge, no luck !
Tried all sources, all DSP programs, nothing changes.
The only thing that did lower the buzz is lowering the AVR display brightness to minimum which makes the buzz acceptable.

So the current situation is, buzz can be heard only if one is near the speakers.
Any sound that is played from HTPC HDMI source mostly or totally covers the buzz, like music from MusicBee or any video from Youtube or VLC player, except the FM radio.
The volume on FM source is really low and the buzz is here louder then on HDMI from HTPC and i have to turn the volume up to cover the buzz.

Is this the AVR crying to be replaced or are the speakers ?

Thanks in advance !
Since this hum is there with only the speakers connected, this is almost certainly RF (radio frequency) interference, most likely picked up in the speaker leads, and fed back to higher gain stages through the negative feedback.

Can you hear this buzz with headphones? If yes, then your preamp sections is probably picking up the RF. If the answer is no, then almost certainly the speaker leads are the source of the RF.

Unfortunately RF interference is becoming a bigger and bigger problem. LED light bulbs are a potent source and light dimmers an even bigger source. SCR dimmers controlling LED light bulbs an even bigger source.

So turn off all LED light bulbs in the house, and make sure all the SCR dimmers are actually turned off and not just set to the lowest setting.

See if that stops the hum.

If you can answer these questions, then there may well be a solution for you.

If you are in an apartment then neighbors may well be the source of the problem.

I think this problem is now getting as common, if not commoner then ground loop problems. Equipment manufacturers now need to do much more to reduce sensitivity to RF. It is long passed time that formal RF rejection needs to be a routine part of bench testing equipment for review.
 
DigitalDawn

DigitalDawn

Full Audioholic
Unplug the coax cable from your cable box and let us know if the hum/buzz goes away. If it does go away then you have a ground-loop.
 
highfigh

highfigh

Audioholic Overlord
Hello all !

Hopefully this will not be my only post here :)

I'm having a trouble with my home theater setup. Recently i've noticed a buzz/hum ( really i can't tell the difference ) coming from the speakers.
Here is the setup:
Yamaha RX-V377
2x Boston Acoustics cs 260 ii
Samsung LED 48" ( kill me i don't know exact model, but i think it's irrelevant )
HTPC with Nvidia 1060 GPU

HTPC is connected to AVR with HDMI, then AVR is connected to TV with HDMI on ARC port.
The setup is used for music/movies/gaminig/Youtube.

I've tried to troubleshoot the problem with disconnecting anything from AVR and leaving only the speakers, but no luck.
Tried connecting AVR to various different power sockets, still buzzing.
Tried connecting AVR to UPS, nothing, still buzzing.
When i mute the volume on AVR, the buzz is still there, changing the volume doesn't change the buzz strength.
Unplugged the ISP router, no change, still buzz. I even did unplug the fridge, no luck !
Tried all sources, all DSP programs, nothing changes.
The only thing that did lower the buzz is lowering the AVR display brightness to minimum which makes the buzz acceptable.

So the current situation is, buzz can be heard only if one is near the speakers.
Any sound that is played from HTPC HDMI source mostly or totally covers the buzz, like music from MusicBee or any video from Youtube or VLC player, except the FM radio.
The volume on FM source is really low and the buzz is here louder then on HDMI from HTPC and i have to turn the volume up to cover the buzz.

Is this the AVR crying to be replaced or are the speakers ?

Thanks in advance !
Hum is low frequency, at 50 or 60 Hz and buzz is higher frequency, usually at some multiple of 50/60 Hz. In tube equipment, hum can be at 120Hz, depending on the rectification.

As mentioned, if the cable from the provider is connected and the hum stops, call them and have them ground their feed properly- this is so common that when people who install AV systems see the symptom, the first thing we think about is the coax feed not being grounded or their equipment is faulty.

If you also see faint diagonal stripes that drift upward on the video display, it generally confirms the diagnosis.
 
A

avesatani

Enthusiast
Thanks for the answers !

@lovinthehd
Yes i did check the article. Mostly everything i've managed to cover except the wire part of the outlets. I'm somewhat scared of doing anything with wires
even when the electricity is completely shut off. On the other hand, i do have LED lights which are off for the most of the time and the buzz is there no matter
if they are off or on. Also i'm unsure do they share the same circuit with the outlet where AVR is plugged. My next step is to take AVR to office or a friends place, if buzz is there, probably i can exclude ground loop issue in my apartment then.

@VMPS-TIII
The AVR is 5 years old so no warranty. Probably it suffers from 'it works fine for 5 years' bug ;) I had an idea to open the AVR and disconnect the cable that goes to the display. Maybe that could be some solution ? Or maybe it could cause some other malfunction.

@TLS Guy
Didn't tried the headphones as i don't use them and don't have any except the ones for the mobile phone. Doubt that they will work.
All LED lights are turned off and the buzz is there. I don't have any SCR dimmers.
The only way to exclude neighbours is to take AVR somewhere else. If it's RF that is affecting the speakers, is there any solution ? In that case replacing the AVR will not help, neither the new speakers ?

@DigitalDawn & @highfigh
I have IPTV, so no coax cable.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Thanks for the answers !

@lovinthehd
Yes i did check the article. Mostly everything i've managed to cover except the wire part of the outlets. I'm somewhat scared of doing anything with wires
even when the electricity is completely shut off. On the other hand, i do have LED lights which are off for the most of the time and the buzz is there no matter
if they are off or on. Also i'm unsure do they share the same circuit with the outlet where AVR is plugged. My next step is to take AVR to office or a friends place, if buzz is there, probably i can exclude ground loop issue in my apartment then.

@VMPS-TIII
The AVR is 5 years old so no warranty. Probably it suffers from 'it works fine for 5 years' bug ;) I had an idea to open the AVR and disconnect the cable that goes to the display. Maybe that could be some solution ? Or maybe it could cause some other malfunction.

@TLS Guy
Didn't tried the headphones as i don't use them and don't have any except the ones for the mobile phone. Doubt that they will work.
All LED lights are turned off and the buzz is there. I don't have any SCR dimmers.
The only way to exclude neighbours is to take AVR somewhere else. If it's RF that is affecting the speakers, is there any solution ? In that case replacing the AVR will not help, neither the new speakers ?

@DigitalDawn & @highfigh
I have IPTV, so no coax cable.
If you have an Ethernet cable connected you need to disconnect that also.

I highly doubt there is anything wrong with the receiver.

Since you are in an apartment, it is dollars to doughnuts your problem is RF interference. All it takes is a neighbor just the change the brand of a bulb and the problem can show up.

This is the typical pattern of RF emitted by a LED light bulb.

1606748394020.jpeg


Although the noise is in the RF band, electronic gear is packed with solid state junctions in a myriad of ICs, transistors and diodes. There can and do, rectify these stray signals, and then you get your buzz.

The variation of the radiation is apparently huge brand to brand. The industry is now marketing low emission LED bulbs for this reason. I understand that bulbs sold though the bulk commercial market have much higher RF. So there may be many bulbs bought and installed by your apartment company creating RF all over the place.

There a a huge number of articles on this in the Internet now. I have encountered it commonly. I am almost 100% certain this is your problem, and by far the most likely cause.

This is the reason they I now recommend that ALL in wall speaker cable be run through grounded steel conduit. All mine are.
 
highfigh

highfigh

Audioholic Overlord
If you have an Ethernet cable connected you need to disconnect that also.

I highly doubt there is anything wrong with the receiver.

Since you are in an apartment, it is dollars to doughnuts your problem is RF interference. All it takes is a neighbor just the change the brand of a bulb and the problem can show up.

This is the typical pattern of RF emitted by a LED light bulb.

View attachment 42193

Although the noise is in the RF band, electronic gear is packed with solid state junctions in a myriad of ICs, transistors and diodes. There can and do, rectify these stray signals, and then you get your buzz.

The variation of the radiation is apparently huge brand to brand. The industry is now marketing low emission LED bulbs for this reason. I understand that bulbs sold though the bulk commercial market have much higher RF. So there may be many bulbs bought and installed by your apartment company creating RF all over the place.

There a a huge number of articles on this in the Internet now. I have encountered it commonly. I am almost 100% certain this is your problem, and by far the most likely cause.

This is the reason they I now recommend that ALL in wall speaker cable be run through grounded steel conduit. All mine are.
Conduit is fine, but unnecessary in most cases. There are literally thousands of miles of cabling in any major city that have gone unaffected by interference without being in metallic conduit but the best way to prevent it is by using the correct dimmers, not running cabling parallel to wiring that make it likely that coupling will occur and through proper termination. Conduit doesn't help with point to point transmission (through the air), either.

However, the NEC allows using plastic J-boxes and when they're housing noise sources (like dimmers), the interference causes problems. The fact remains- proper grounding would minimize this and I don't think the AV equipment manufacturers test for intrusion of interference.
 
A

avesatani

Enthusiast
I do understand the possible RF issue in general but can't troubleshoot the neighbours LED bulbs or any other source.

There are a few other things that i'll try to do, replace 2 of possible problematic power sockets and change a possible problematic light switch.
Other then that, only to take the AVR somewhere else and plug it there.

Anyway, I really appreciate the answers, thanks a lot ! :)
 
highfigh

highfigh

Audioholic Overlord
I do understand the possible RF issue in general but can't troubleshoot the neighbours LED bulbs or any other source.

There are a few other things that i'll try to do, replace 2 of possible problematic power sockets and change a possible problematic light switch.
Other then that, only to take the AVR somewhere else and plug it there.

Anyway, I really appreciate the answers, thanks a lot ! :)
You can't change the neighbors as a possible source, but there are ways to determine if noise is airborne. AM radio is a good noise 'sniffer', as is the wand used for identifying cables in communications cabling. The buzz becomes louder as the distance to the source decreases.

You can also move equipment, as a way to determine how some noise enters the system- rotate it 90 degrees on its shelf, if possible. Orientation when magnetic fields are causing the connection changes the extent of intrusion.
 
lovinthehd

lovinthehd

Audioholic Jedi
I like your idea of taking it to another environment to see if its the receiver, does sound like you've covered much of what else you can do. One thing I like to try with something like this are resets (sounds like you did a soft reset), so try a full factory/microprocessor reset per your manual....
 
pcosmic

pcosmic

Full Audioholic
Hello all !

Hopefully this will not be my only post here :)

I'm having a trouble with my home theater setup. Recently i've noticed a buzz/hum ( really i can't tell the difference ) coming from the speakers.
Here is the setup:
Yamaha RX-V377
2x Boston Acoustics cs 260 ii
Samsung LED 48" ( kill me i don't know exact model, but i think it's irrelevant )
HTPC with Nvidia 1060 GPU

HTPC is connected to AVR with HDMI, then AVR is connected to TV with HDMI on ARC port.
The setup is used for music/movies/gaminig/Youtube.

I've tried to troubleshoot the problem with disconnecting anything from AVR and leaving only the speakers, but no luck.
Tried connecting AVR to various different power sockets, still buzzing.
Tried connecting AVR to UPS, nothing, still buzzing.
When i mute the volume on AVR, the buzz is still there, changing the volume doesn't change the buzz strength.
Unplugged the ISP router, no change, still buzz. I even did unplug the fridge, no luck !
Tried all sources, all DSP programs, nothing changes.
The only thing that did lower the buzz is lowering the AVR display brightness to minimum which makes the buzz acceptable.

So the current situation is, buzz can be heard only if one is near the speakers.
Any sound that is played from HTPC HDMI source mostly or totally covers the buzz, like music from MusicBee or any video from Youtube or VLC player, except the FM radio.
The volume on FM source is really low and the buzz is here louder then on HDMI from HTPC and i have to turn the volume up to cover the buzz.

Is this the AVR crying to be replaced or are the speakers ?

Thanks in advance !
My money's on your PC. Turn off/unplug your PC!! IF the noise goes away, the culprit is your PC. UPS won't help. You may need to experiment with a isolation trans/power conditioner
 
A

avesatani

Enthusiast
I like your idea of taking it to another environment to see if its the receiver, does sound like you've covered much of what else you can do. One thing I like to try with something like this are resets (sounds like you did a soft reset), so try a full factory/microprocessor reset per your manual....
Done that, think it's power+some other button at the same time. Other environment is the next step, have to find the healthy one.

My money's on your PC. Turn off/unplug your PC!! IF the noise goes away, the culprit is your PC. UPS won't help. You may need to experiment with a isolation trans/power conditioner
Well Sir, please give me your money ;) Nope, PC is not the issue since only thing that was connected during troubleshooting was AVR & speakers. No other equipment were connected to the power source or the AVR itself.
 
Last edited:
TLS Guy

TLS Guy

Audioholic Slumlord
Done that, think it's power+some other button at the same time. Other environment is the next step, have to find the healthy one.



Well Sir, please give me your money ;) Nope, PC is not the issue since only thing that was connected during troubleshooting was AVR & speakers. No other equipment were connected to the power source or the AVR itself.
It is too bad you can't do the headphone test. If we could isolate the pickup to the speaker leads, then simple RF chokes can be inserted on the +ve side of the speaker leads at the receiver +ve terminals. That will almost certainly solve your problem.
 
A

avesatani

Enthusiast
It is too bad you can't do the headphone test. If we could isolate the pickup to the speaker leads, then simple RF chokes can be inserted on the +ve side of the speaker leads at the receiver +ve terminals. That will almost certainly solve your problem.
Will buy the adapter for the headphones, it costs 2€ and will give it a try with the ones that i have.
 
A

avesatani

Enthusiast
An update, no buzz on headphones o_O

I've used the Samsung headphones that came with mobile phone connected to the adapter, if that makes any difference.
However, i had to turn the volume up a lot to be able to hear anything and sound quality is really poor. Tried FM radio and HDMI source from PC, both sounded like an old and broken device.
For example, MP3 from MusicBee through ASIO, vocal sounds as someone singing through a metal foil.
 
TLS Guy

TLS Guy

Audioholic Slumlord
An update, no buzz on headphones o_O

I've used the Samsung headphones that came with mobile phone connected to the adapter, if that makes any difference.
However, i had to turn the volume up a lot to be able to hear anything and sound quality is really poor. Tried FM radio and HDMI source from PC, both sounded like an old and broken device.
For example, MP3 from MusicBee through ASIO, vocal sounds as someone singing through a metal foil.
Well the quality is due to the poor headphones. Do you know someone who has a good pair of headphones, so we can be sure it is the power amp section picking up the buzz.

Alternatively you could just go ahead and install the RF blockers. They are cheap.
 

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