Unknown electrical complication affecting my audio system

[Xen]

Just so I understand. You @Xen are talking about your device now, which buzzes/hum in your apartment which doesn't buzz/hum at Lampizator and Audionet when they tested. Is that correct?
How do you know if they don't just say there's no buzz/hum? I mean it's subjective. They may not have experienced it the way you do. So I think you should follow Solderdude's advice.

I understand your point. I will pick the small device and test it in other environment. It's also awkward to try to find an excuse so I can be able to plug it somewhere.

Just to clarify a buzz has particular characteristics and is a well defined sound, there is no room for interpretation.

 

[SSS]

I understand your point. I will pick the small device and test it in other environment. It's also awkward to try to find an excuse so I can be able to plug it somewhere.

Just to clarify a buzz has particular characteristics and is a well defined sound, there is no room for interpretation.

Could you please record the buzz and put the buzz.wav file here?

 

[Peterinvan]

Another thought... have the bolts that hold the transformers worked loose?

 

[Xen]

I couldn't attach the wav files only recognize compressed. The phone mic is not sensible enough!!

 

[DanielT]

I couldn't attach the wav files only recognize compressed. The phone mic is not sensible enough!!

Sounds like a transformer humming to my ears.A little hard to hear though. If more knowledgeable people (I'm just a happy hobby amateur ) think it's something else you're hearing, please tell us.

As I and others in the thread have suggested:
Open up your amp and check that the screws/bolts holding the transformer are properly tightened. A little more extensive work than that, see #5 in the thread.

By the way, what type of transformer is that?

 

[Xen]

Sounds like a transformer humming to my ears.A little hard to hear though. If more knowledgeable people (I'm just a happy hobby amateur ) think it's something else you're hearing, please tell us.

As I and others in the thread have suggested:
Open up your amp and check that the screws/bolts holding the transformer are properly tightened. A little more extensive work than that, see #5 in the thread.

By the way, what type of transformer is that?

There are two files DAC-Gryphon, the DAC just arrived from the producer, and I am not going to open a 30 months old amp.

As said before it's an irregularity electrical signal that causes interference that affects the equipments. This started while there has been no changes in the apartment.

I am just trying to narrow down what kind of disturbances in the current could cause this???

 

[Sokel]

Apologies if already defined, but all three trafos (four if the Gryphon is of the ones I know) hum?
Even on their own, tested each without the rest of the gear connected to mains?

 

[DanielT]

There are two files DAC-Gryphon, the DAC just arrived from the producer, and I am not going to open a 30 months old amp.

As said before it's an irregularity electrical signal that causes interference that affects the equipments. This started while there has been no changes in the apartment.

I am just trying to narrow down what kind of disturbances in the current could cause this???

Ok. But do this. Plug in somewhere other than your apartment and listen for yourself and with that:
If you don't hear this buzz, the problem is in your apartment.
If you hear buzz, open up.

Does that sound reasonable?

 

[Sokel]

For the troubleshooting ninjas, that's the chart of the two recordings:

 

[solderdude]

The problem with recording something that is very low in level using a microphone in very close proximity to a device that has a stray magnetic field (as most transformers/filters aren't fully shielded with a mu-metal enclosure almost all gear does) is that a microphone and/or the circuit wiring inside can pick up that magnetic field. This can create the effect that such a recording can show measurable differences that were not present acoustically.

The only conclusive test that can be done is to listen to the amp for hum in a totally different location. If it doesn't hum there but does in the apartment then something is wrong in that apartment with the mains voltage.
When it hums similarly in another building it just is the device itself.

The fact that it suddenly happened could also be caused by hearing it (say in the evening when the hearing is most sensitive) and once you hear something one usually can't unhear it anymore. Especially when it is annoying.
So it may always have hummed but might not have been perceived.

For that reason ... take the humming device to any other location (not being the building itself) and listen to the device itself.
After that report back and if is did not hum equally loud it is time to investigate further (hum does not make it in the audio itself so that is not a problem).

 

[Xen]

I tried with the spectroid app but I couldn't do any recording. I have noticed peaks in the 50hz how should I interpret it?
Let me see how I will go around with any equipment in the underground!

 

[SSS]

Listened to the audio files. Hard to interpret. For me it does not sound like a mains transformer. If the unit has a small fan, I would estimate that this is bearing noise. I had similar noise from a fan in a car battery charger.

 

[Xen]

Certainly you can perceive the buzz with a phone, specially in one of the files. Is not my only opinion after asking few persons.

 

[DanielT]

I also have a small device with transformer inside and hear the typical buzzing sound from the transformer when I get close to it. Is in the power grid of the apartment.

There you can take the first step. Take the small device to another location and plug it in there and listen. Then you will immediately discover whether it is the power grid of the apartment that is causing the buzz or not.

I mean if it's a small device you can do it today.

It should be the same type of outlet, grounded or not, but the same type in your apartment as in the other location.

 

[SSS]

Certainly you can perceive the buzz with a phone, specially in one of the files. Is not my only opinion after asking few persons.

After digging in the dark, which is your amp/pre/DAC product? Producer, model type? This to better understand what gear it is.

 

[Balle Clorin]

Maybe the electrical load in the building has changed? The load will affect the shape of the AC waveform and possibly trigger transformer vibration/magnetostriction more than before.

The mains noise and AC balance in my building changed completely after upgrading the building electrical intake for a higher load. noise measured with a EMI meter from Alphalabs and imbalance went down. Did not affect my hifi in any (audible) way…

Listen with stethoscope to a device and there will “always” be some audible buzz coming from the power supply

Sad to hear about your situation


This is me checking the mains noise before the change to the electrical input, After the change the noise value is about 30mV.. not 699 or 1567mV.. Please note I had no problems with my hifi before nor after

What the meter reads is probably unrelated to your problem, but anyway here is the specs

Line EMI Meter

Power Line Meter which measures high frequency electric fields present on your power lines in milliVolts. It captures frequencies between 10 KHz and 10 MHz. These high frequency electric fields are commonly known as Dirty Electricity.

safelivingtechnologies.com

, the filters I tried did nothing to my hifi..I was just curious


This gives some general guidelines for noise troubleshooting

Power Line Noise

The American Radio Relay League (ARRL) is the national association for amateur radio, connecting hams around the U.S. with news, information and resources.

www.arrl.org

 

[Xen]

Maybe the electrical load in the building has changed? The load will affect the shape of the AC waveform and possibly trigger transformer vibration/magnetostriction more than before.

The mains noise and AC balance in my building changed completely after upgrading the building electrical intake for a higher load. noise measured with a EMI meter from Alphalabs and imbalance went down. Did not affect my hifi in any (audible) way…

Listen with stethoscope to a device and there will “always” be some audible buzz coming from the power supply

Sad to hear about your situation


This is me checking the mains noise before the change to the electrical input, After the change the noise value is about 30mV.. not 699 or 1567mV.. Please note I had no problems with my hifi before nor after

What the meter reads is probably unrelated to your problem , must anyway

Line EMI Meter

Power Line Meter which measures high frequency electric fields present on your power lines in milliVolts. It captures frequencies between 10 KHz and 10 MHz. These high frequency electric fields are commonly known as Dirty Electricity.

safelivingtechnologies.com

, the filters I tried did nothing to my hifi..I was just curious

Thanks for the comment!
After trying an Isotek DC blocker and a Puritan the humming inside is still there, at the same time I am concerned that exposing the equipment could deteriorate the components.

Probably I will get an emi meter, then I wonder what I would do with the measurements. Within the next month the Electric company is going to change to digital main meters, usually they make some continuous measurements, and I can talk with them directly.

 

[solderdude]

Thanks for the comment!
After trying an Isotek DC blocker and a Puritan the humming inside is still there, at the same time I am concerned that exposing the equipment could deteriorate the components.

It won't. Even when the mains would have lots of harmonics there is not a single component that could deteriorate by this.

Probably I will get an emi meter, then I wonder what I would do with the measurements. Within the next month the Electric company is going to change to digital main meters, usually they make some continuous measurements, and I can talk with them directly.

EMI meter will only show HF not mains frequencies/harmonics.


Have you tried the amp at another location ?

 

[Xen]

The amp is like 50kg, but the DAC & pre were fully inspected in the factory( normal environment) no sign of humming. Probably I will take one component and check somewhere.

This started after hearing humm in the whole living room even do when everything was disconnected, an hour later I heard movement in my neighbor apartment, right after the humming in the room stop.

EMI meter will only show HF not mains frequencies/harmonics.

Here in Germany a normal electric company doesn't have sophisticated equipment to do this measurements. Companies at this level for private homes are quite expensive.

 

[Balle Clorin]

This started after hearing humm in the whole living room even do when everything was disconnected, an hour later I heard movement in my neighbor apartment, right after the humming in the room stop

This must be an important clue..