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AVR buzz

I've got a little Yamaha receiver that at some point in time has developed a buzz. I first noticed it about 2 days ago, but due to it being hot and our AC dying, it could very well have been longer and I just didn't notice it with the fan on. I've seen actually very little information online, but based on my paltry troubleshooting I think it might be the power supply.

It's running as a sort of HTPC setup, PC, and sub plugged into a power strip, then into the same GFCI outlet. Based on a diagram I saw, having them plugged into the same outlet should prevent a ground loop, but I'm no expert. It also stated that the sound should be coming from the speakers. If it matters, the monitors are plugged into another outlet.

The buzz is coming from the unit itself, there is no sound coming from the speakers.

It could maybe be unshielded cables? I'm not sure. I'm just running some of the generic Amazon Basics HDMI cables, though everything is in more or less one big bundle.

I have removed the inputs/outputs... though I didn't wait very long... but the noise remained.

I have turned it off for ~1 hour, then turned it back on to buzz again, after a long off period i.e. overnight, it starts off quiet.

I have NOT tried to plug it in to another outlet because... hassle. It's never fun to have to hook these back up again in small spaces.

 

Does anyone have any ideas? It's not terrible, and I could probably learn to ignore it, but would be best if it went away.

#Muricaparrotgang

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It's usually caused by interference from another device. If you have lights nearby the receiver, turn them off. Especially LEDs, the wall warts tend to hum and buzz like wild gorillas.

 

Sometimes buying more expensive cables can help in a situation like this. The Amazon Basics doesn't offer much shielding. 

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I don't have any lights or LEDs near it, but it is in close proximity to my PC, however the noise hasn't always been there. Wouldn't the buzz be there from the get go or no?

#Muricaparrotgang

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  • 2 weeks later...

Disconnect everything from the AVR aside from the speakers then turn the AVR on. If the buzz is no longer there, chances are it's a ground loop. Are you still using any analogue interconnect?

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  • 2 weeks later...
On 11/28/2017 at 2:26 PM, Stagea said:

Disconnect everything from the AVR aside from the speakers then turn the AVR on. If the buzz is no longer there, chances are it's a ground loop. Are you still using any analogue interconnect?

I have removed everything but the speakers and the buzz is still present. The only connections I have going in are PC via HDMI, PS4 via HDMI, and HDMI out to my monitor. I'm again unsure what exactly causes ground loops, but everything is plugged into the same outlet.

Later on I plugged in my electric guitar near my PC and realized it was making a horrible screeching sound in the area, as my PC and receiver are ~3 feet apart. Even moving my guitar to the other side of my desk made the sound go away. So there IS a lot of EMF going on, so I'm wondering if John is right and I need better cables with more shielding.

#Muricaparrotgang

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On 12/10/2017 at 12:54 PM, JZStudios said:

I have removed everything but the speakers and the buzz is still present. The only connections I have going in are PC via HDMI, PS4 via HDMI, and HDMI out to my monitor. I'm again unsure what exactly causes ground loops, but everything is plugged into the same outlet.

Later on I plugged in my electric guitar near my PC and realized it was making a horrible screeching sound in the area, as my PC and receiver are ~3 feet apart. Even moving my guitar to the other side of my desk made the sound go away. So there IS a lot of EMF going on, so I'm wondering if John is right and I need better cables with more shielding.

Did you disconnect the subwoofer too?

 

If it's happening with no other cables hooked up to the AVR, then better cables will not save you from the issue (since a good cable is not quieter than no cable).

 

 

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On 12/11/2017 at 6:20 PM, Stagea said:

Did you disconnect the subwoofer too?

 

If it's happening with no other cables hooked up to the AVR, then better cables will not save you from the issue (since a good cable is not quieter than no cable).

 

 

I believe I did since I had pulled the receiver away to plug it into another outlet. The only thing I've done since is take the top off, scrape off some paint in an inconspicuous area and clamp a ground wire to it then pitting the other end on the mounting screw on the electrical outlet. That's supposed to help grounding but I'm not sure if it's working.

I think I'll try the cables just in case and return them if need be, but even the higher quality ones with shielding I'm looking at are less than a dollar per foot so it's not that big a loss.

 

Otherwise is it just an unfixable issue with the receiver?

#Muricaparrotgang

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It's likely the buzz is one specific component that is vibrating and is not ground related at all  (ground loops are usually heard in the speakers).  It's not unknown for coil-style transformers to buzz.  Small surface mount coil transformers are particularly noteworthy. One thing you can do is:

1. remove the lid.

2. power it on.

3. try to isolate the buzz by ear.

4. try applying pressure to individual components on the board with an insulated instrument (handle of a screw driver, etc.) to see if you can determine which component it is.

 

Nothing is unfixable, but electronics service costs can be high ($80 - $200 per hour).  If you can find out what it is, that will help reduce the time needed by a tech to troubleshoot.

 

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My bad. I missed the part that it was *not* coming from the speakers. If it's coming from the unit itself, it's likely from the linear power supply. The transformer may have the wingdings or the core coming loose. Sometimes the core can be re-tightened (if fixed together with screws), or damped. If it's not serviceable, the entire transformer can always be replaced.

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11 hours ago, Stagea said:

My bad. I missed the part that it was *not* coming from the speakers. If it's coming from the unit itself, it's likely from the linear power supply. The transformer may have the wingdings or the core coming loose. Sometimes the core can be re-tightened (if fixed together with screws), or damped. If it's not serviceable, the entire transformer can always be replaced.

I kind of figured it might be power related. Maybe if it's a cheap part I'll replace it, otherwise it's a $200 receiver and it's not a huge deal if I just get another one in a few months and stick this in the living room or something.

I'll look to see if I can tighten anything up, and I still think I might want to go ahead with the cables just to reduce the EMF noise field anyways.

#Muricaparrotgang

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