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Ohhh. Thanks for this answer. I'll look at this more closely. So you are talking about something like this? https://www.pooraudiophile.com/2015/03/how-to-fix-dc-offset-and-transformer.html

I'll post a reply later with more info. Thanks!

Here is at least all you wanted to know about causes and effects of DC on powerlines and how to block it.

http://sound.whsites.net/articles/xfmr-dc.htm

At least one company, Bryston, includes DC blocking in at least some of their power amplifiers, for example the 4BSST2. The schematic is online.
 

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Here is at least all you wanted to know about causes and effects of DC on powerlines and how to block it.

http://sound.whsites.net/articles/xfmr-dc.htm

At least one company, Bryston, includes DC blocking in at least some of their power amplifiers, for example the 4BSST2. The schematic is online.
Thanks for the information! But I'm missing something: Why my AVR only makes this high-pitch hum/buzz sound from the transformer when on "Stand-By"? The "hum/buzz" sound completely stops when I power on the receiver... Strange...:confused:
 

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Ohhh. Thanks for this answer. I'll look at this more closely. So you are talking about something like this? https://www.pooraudiophile.com/2015/03/how-to-fix-dc-offset-and-transformer.html

I'll post a reply later with more info. Thanks!

***OH, and you are not talking about EMI/RFI Noise right?
Yes, you want a device which blocks DC which may be present on your AC power line. DC is not the same thing as EMI/RFI; those are high frequency components which are riding on your power line. A good EMI/RFI filter will block those. Note that a "surge protector" is not either of those types of filter. In fact a surge protector doesn't filter at all, it just trips a circuit breaker if the line voltage surges above a set level, which is usually something around 400 VAC.

I think Emotiva will allow you to return their filter if it proves to not cure your particular case of transformer buzz. You could always have gotten unlucky and simply have an amplifier which has a transformer which was not wound at proper tension or some other defect. But try the DC blocker first.

Regarding why your transformer buzzes at idle and not under load, that is not surprising. Exactly what is going on can get complex, but that behavior is not necessarily abnormal or a symptom of a particular fault.
 

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I can only guess that its not your amp but wiring into home...I have spent months in foreign countries where this can be a problem.
 

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Yes, you want a device which blocks DC which may be present on your AC power line. DC is not the same thing as EMI/RFI; those are high frequency components which are riding on your power line. A good EMI/RFI filter will block those. Note that a "surge protector" is not either of those types of filter. In fact a surge protector doesn't filter at all, it just trips a circuit breaker if the line voltage surges above a set level, which is usually something around 400 VAC.

I think Emotiva will allow you to return their filter if it proves to not cure your particular case of transformer buzz. You could always have gotten unlucky and simply have an amplifier which has a transformer which was not wound at proper tension or some other defect. But try the DC blocker first.

Regarding why your transformer buzzes at idle and not under load, that is not surprising. Exactly what is going on can get complex, but that behavior is not necessarily abnormal or a symptom of a particular fault.
Thanks so much for all the information. I'll definitely give it a try. Cheers!:)

***EDIT: Emotiva CMX-2 device on the way..! More news to come!
 

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Thanks for your help! But the "HUM/BUZZ" sound that comes from MANY Yamaha RX-A Aventage units comes from a defective transformer. period.
Agreed. Also, only a really mediocre EI transformer will hum. Physical hum is more common, but not still not very common at all, with toroidal transformers.
 

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Thanks for the information! But I'm missing something: Why my AVR only makes this high-pitch hum/buzz sound from the transformer when on "Stand-By"? The "hum/buzz" sound completely stops when I power on the receiver... Strange...:confused:
Inside the AVR are (2) transformers...
1st is the large, main power transformer and the 2nd is the smaller transformer which powers the remote sensor when in stand-by mode..

Just my $0.02... ;)
 

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Inside the AVR are (2) transformers...
1st is the large, main power transformer and the 2nd is the smaller transformer which powers the remote sensor when in stand-by mode..

Just my $0.02... ;)
Oh, so the 2nd transformer might be defective then? :crying:
 

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just want to share my fix or workaround for the issue.
I have just bought a refurbished yamaha 5830 receiver from internet and there is hum from transformer. it can be heard from my couch 10 feet away when i watch movie at low volume at night. even though it is still under warranty, i don't want to bother to send it in or drive to the nearest dealer to have it fixed possibly. so i opened it up. the transformer is well varnished. there is only a little hum if i approach my ear to it but not too bad. the thing is, the enclosure is resonant. so if the transformer is mounted to the bottom of the frame the whole enclosure will amplify the hum and even worse, the hum will be reflected in the slot of my tv console.
so i cut four rubber gaskets out of the flat tire of my kid's bike and used them as damper for the transformer mount.(shown in the picture is one of the 4 bolts that needs to be damped, i put rubber between the frame and transformer) after that, the hum is not audible from my couch anymore, not even 1 feet away. it can be only heard if i put my ear on the face plate of the receiver.
Hope this helps people bothered by the hum.

PS. i also tested DC offset while researching the cause of the hum and thinking of trying emotiva cmx2 but it was only 20mv max so it is within normal range.
 

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