Denon AVR-X1100W Buzzing From Receiver

[SupaMonkey]

Hi Guys,
Have a Denon AVR-X1100W and this week it decided to start buzzing (not a low hum or a drone, but a buzz - I'd guess around 120Hz). Changing/disconnecting sources / speakers doesnt do anything - its coming directly from the receiver.
I'm from South Africa and sending this back to Denon is just going to be a headache and cost a fortune (and yes, its quite a few years old - so out of warranty). Is there anything I can do myself under the hood to try resolve this myself?

Thanks in advance!

 

[lovinthehd]

Maybe check the power transformer and see if it's become loose? At least from your description of a physical buzzing with the unit only plugged into power that would be my suspicion. Recently had an old amp that had something similar going on so I tightened the screws a bit and the noise disappeared (so far ).

 

[TLS Guy]

Maybe check the power transformer and see if it's become loose? At least from your description of a physical buzzing with the unit only plugged into power that would be my suspicion. Recently had an old amp that had something similar going on so I tightened the screws a bit and the noise disappeared (so far ).

I agree with lovin. There is only one cause of this and that is a problem with the mains transformer. Either the core laminations are coming loose, or the transformer windings are coming loose, due to the transformer not being properly potted.

The only thing you can do is make sure the mounting screws are really turned down hard. If that does not do the trick only replacing the power transformer would solve it.

That receiver is coming up on seven years old. More than likely parts would not be available. In any event that would be a very expensive repair. If the buzz is too loud to tolerate I recommend you replace it. In any event, unfortunately 7 years is within the normal life expectancy of receivers. So that honestly makes expensive repair unwise.

 

[lovinthehd]

I agree with lovin. There is only one cause of this and that is a problem with the mains transformer. Either the core laminations are coming loose, or the transformer windings are coming loose, due to the transformer not being properly potted.

The only thing you can do is make sure the mounting screws are really turned down hard. If that does not do the trick only replacing the power transformer would solve it.

That receiver is coming up on seven years old. More than likely parts would not be available. In any event that would be a very expensive repair. If the buzz is too loud to tolerate I recommend you replace it. In any event, unfortunately 7 years is within the normal life expectancy of receivers. So that honestly makes expensive repair unwise.

Where did you get that receiver life expectancy figure? I have three in use older than that....

 

[TLS Guy]

Where did you get that receiver life expectancy figure? I have three in use older than that....

I don't remember for sure. However what I said does not mean that all receiver will fail in 7 years, most will likely last longer. That is the time after which failure starts to become progressively more likely. In addition manufacturers are supposed by law to keep parts available for seven years, but that is another law never enforced!

My experience here with failure posts certainly gives me the impression that most failures are in the 7 to 15 year age window.

 

[lovinthehd]

I think they simply are more likely to be obsolete technology wise, if taken care of they can last quite a while, at least as much as most consumer electronics.

 

[MichaelX]

Hello All,

New to the forum. I wish i found it sooner, before needing help but here i am..

I have the same problem as SupaMonkey. A 50 Hz or so buzz from the power transformer. However it also seems to come from the switchmode power supply that is between the mains plug and the power transformer.

I can't really hear where it's coming from since i don't feel confortable putting my ears too close to a live power supply.

Is there a way to determine of the humm is coming from the SMPS or the Power Transfomer?

Also the buzzing stops when the avr is on for a few minutes and warm to the touch.

 

[TLS Guy]

Hello All,

New to the forum. I wish i found it sooner, before needing help but here i am..

I have the same problem as SupaMonkey. A 50 Hz or so buzz from the power transformer. However it also seems to come from the switchmode power supply that is between the mains plug and the power transformer.

I can't really hear where it's coming from since i don't feel confortable putting my ears too close to a live power supply.

Is there a way to determine of the humm is coming from the SMPS or the Power Transfomer?

Also the buzzing stops when the avr is on for a few minutes and warm to the touch.

That will be the power transformer for sure. It is not properly potted. As the transformer heats up it expands, and everything tightens up. I would not worry about it. It will not affect performance or likely be the cause of failure in the future.

 

[MichaelX]

That will be the power transformer for sure. It is not properly potted. As the transformer heats up it expands, and everything tightens up. I would not worry about it. It will not affect performance or likely be the cause of failure in the future.

Thats what i figuered, but it is very noticable. especially at night when volume is rather low to not wake anyone.
But thank you, i feel confident enough to just replace it now.

 

[highfigh]

Place a finger on the top and if the sound stops, it's just a sympathetic vibration. Make sure the screws for the cover are snug.

 

[MichaelX]

Place a finger on the top and if the sound stops, it's just a sympathetic vibration. Make sure the screws for the cover are snug.

Hi,

With the cover off it still buzzes. I don't feel any vibrations when touching the power transformer. I found a parts shop thet sells the transformer and provides money back guarantee. I can easily test if its fixed with a new transformer.

Thanks all!

 

[Oneeshitwonder]

I recently went thru another utility power failure and after power was restored for awhile one of my receivers was buzzing annoyingly. Having a FLuke meter with A/C Hz reading feature I checked the Hz's and the voltage my house was getting from the power company. The Hz was 59.96 to 59.99 and the voltage was 123.1to 124.2 in fluctuation on average using the Logging feature. Later when the buzzing stopped I checked house power again and the Hz was 60.01 to 60.02 being more often at 60.02 and the voltage was a steady 124.4.
I also have noticed my hot tubs and house hot water recirculation pumps make annoying noises for awhile after a power outage. I noticed in the past that well after a power outage that my voltage and hz's are near perfect with 120V even and hz's near perfect with a .01 fluctuation at 60.00 to 60.01
I suspect that after the power company does repairs they have to tweek things a little to get things back to normal.
Once when this particular receiver was buzzing I tilted in up and back a little and put a small towel under it and that made the buzzing go away. But I don't remember if a power failure had occurred just before. Also I suspect that this buzzing can happen at any time with no recent power outages near you because the electrical grid is a huge things and problems occur all the time far away from my house and the voltage and Hz will likely be a bit off from time to time.

 

[TLS Guy]

I recently went thru another utility power failure and after power was restored for awhile one of my receivers was buzzing annoyingly. Having a FLuke meter with A/C Hz reading feature I checked the Hz's and the voltage my house was getting from the power company. The Hz was 59.96 to 59.99 and the voltage was 123.1to 124.2 in fluctuation on average using the Logging feature. Later when the buzzing stopped I checked house power again and the Hz was 60.01 to 60.02 being more often at 60.02 and the voltage was a steady 124.4.
I also have noticed my hot tubs and house hot water recirculation pumps make annoying noises for awhile after a power outage. I noticed in the past that well after a power outage that my voltage and hz's are near perfect with 120V even and hz's near perfect with a .01 fluctuation at 60.00 to 60.01
I suspect that after the power company does repairs they have to tweek things a little to get things back to normal.
Once when this particular receiver was buzzing I tilted in up and back a little and put a small towel under it and that made the buzzing go away. But I don't remember if a power failure had occurred just before. Also I suspect that this buzzing can happen at any time with no recent power outages near you because the electrical grid is a huge things and problems occur all the time far away from my house and the voltage and Hz will likely be a bit off from time to time.

Those frequency and voltage measurements are well within the allowed specification and will not cause a problem.