unbalanced mic humming in usb dac

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poisas

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Hi, i just bought Yamaha AG06 usb mixer/dac. This dac has unbalanced 3.5mm jacks for mic and headphones - gaming headset. And i have humming when i use that 3.5mm mic. Actualy it hums pluging any 3.5mm jack cable into it.

And i find out that i have electricity problem. Humming goes away if i turn laptop power adaptor off. https://www.youtube.com/watch?v=o7yHYAuMP8A this indian guy shows the same issue like me. And its not ground issue, if i connect pc vian not grounded socket, i get much bigger humming sound.

ANother symptom that humming sound goes away if i touch anything that is connected to the ground.

Symptom 2: if i use xlr mic on xlr witch is balanced there is no hum.

If i use mobile phone usb charger to power up the mixer and test with headset there is hum also. Humm increases if i touch headsets cord.

for me i cannot unplug because i use not laptop but pc. So my question is how to clean that buzzing humming or how you englishman call that noise?
I would like to hear if there is any sort of "filter" like usb filter, or socket filter, to clean electry ? cause its like my streets electry problem, because i have tryed in all my neighbours and its the same, then i get it to the audio shop, and there is no buzz-humming. Its not fair.. i want clean sound.. Because i have a gaming headset i want to use for game streaming..

Any help would be apreacheated.

I dont think powered usb hub could help, since phone charger is causing same noise.. and i find its not ground loop.. and not a bad psu ( i have seasonic g750w) cause the case is in all power sockets withh all laptops i have its the same. noise goes away when i unplug charger from wall..
 
"ANother symptom that humming sound goes away if i touch anything that is connected to the ground."

At a guess I'm thinking the ground from the AC wall outlet supplying power to the laptop or desktop is not very well connected through to the case of the mixer to ground it and the 3.5mm mic cord is acting sort of like an antenna picking up stray AC that is in the room. When you touch something grounded you act as a 'drain' to shunt the AC.
- On the desktop PC have you tried different USB ports?
- Try a different USB cable, possibly one with ferrites (like this > https://www.amazon.com/Tripp-Lite-H...coding=UTF8&psc=1&refRID=QY0DACEC17CET60A20R5). Ferrites are more for high frequency noise, but won't harm to try.

As a test, try connecting a temporary wire from the metal case of the desktop PC to the outer metal part of one of the RCA jacks on the mixer. If the hum decreases or goes away it may indicate the mixer not being grounded well.
 
Some parts of the world use a "floating" mains supply. This means that unlike our UK supply the Neutral wire is not earthed (it is the common centre of the 3 windings of the 3phase sub transformer).

A floating supply is inherently "safe" from giving you a lethal shock from live to earth but ONLY so long as it remains floating! If someone earths a piece of faulty gear then all safety bets are off since you won't KNOW it is faulty until YOU get a shock. In UK of course such a fault would trip a breaker.

Such floating supplies are fine (and cheap!) for utility use, heating, motors even TV but any kind of "quality" audio application will be bedevilled with noise. I can only assume professional studios have their own electrical supply arrangements? One such would be a Big Mother, double wound isolating transformer. On the secondary side of that you can do as you like and will not endanger the rest of the population!
N.B! The installation of such a transformer requires the expertize of a good electrician and moreover one totally familiar with the needs of an audio system.

Dave.
 
I have tryde with the wire to touch variuos parts, pc, ground pin in socket, no change. Also i have to notice that noise is very little, and only can be audible when gain is crancked up. Its much louder if i use ungrounded plug. What im thinking now is would a usb galvanic isolation fix this humming? Or a device like usb isolator from hifimyaudio? Im looking for a hardware solution
 
You might LIKE a hardware solution but that does not mean there IS one!

This problem of local hum due to a less than splendid electricity supply is a very common one in forums, often there is no cheap, easy solution.

We need to know some very specific things. What country are you actually in? Do you have the services of a really good electrician and is the electricity supply company useful in terms of customer support?

You see, IF the mains supply IS of the "earthed neutral" form you might have a poor local earthing situation and an ELECTRICIAN (or power company) could investigate that and perhaps improve it. However IF it is a floating supply YOU MUST NOT MAKE AD HOC EARTHS TO IT!

Dave.
 
ecc83 said:
You might LIKE a hardware solution but that does not mean there IS one!

This problem of local hum due to a less than splendid electricity supply is a very common one in forums, often there is no cheap, easy solution.

We need to know some very specific things. What country are you actually in? Do you have the services of a really good electrician and is the electricity supply company useful in terms of customer support?

You see, IF the mains supply IS of the "earthed neutral" form you might have a poor local earthing situation and an ELECTRICIAN (or power company) could investigate that and perhaps improve it. However IF it is a floating supply YOU MUST NOT MAKE AD HOC EARTHS TO IT!

Dave.
Click to expand...

Hi, i wonder if this device could fix my issues ? anyone have tried ? Hifime High-Speed USB Isolator
 
As Dave had stated let us know where in the world you are located and if the outlets you plug into have a ground connection (a third connection in the outlet possibly)
What I suggested was on the premise you are located in a country where it is standard by code to have a neutral which is in some way grounded/earthed. I worked for a power utility for some 30 years and at least in the US most all services to residences are required by code to be grounded either as a single phase three wire or three phase, four wire wye connected system. It very well could be different in other parts of the world, but find it hard to fathom a system installed by a legitimate power company that would not provide a grounded service at a residenc

Could you post a short recording of the hum/buzz? It may help in figuring out if it is actually a power issue or possibly USB induced noise.
 
Laptop power supplies are notoriously awful whenever audio connections are made. The MAC people laugh at the PC people because you can get perfectly fine audio from MACs by jus connecting a mega PA to the headphone socket. Most but not all PCs suffer badly from their switch mode power supplies. Dell are probably the worst ones - and some have blamed their ID system that tells the computer if it is a genuine Dell PSU. While non-Dell PSUs often generate a message "This power supply cannot charge the battery on this laptop" however, you might find that an alternate PSU does not produce the hum. Most laptops have modest requirements from a PSU - adequate current and the right voltage. Well worth trying a different one? If you are using a mains power computer and can't do this, then the only real solution would be to source an autotransformer - it's a simple but quite heavy device that has a transformer with two windings, so it produces full mains voltage on the secondary, but it is floating and not normally referenced to ground. Using one, you then ground the computer and all your audio equipment to the real ground in your space. There are some implications with any specific protection you have. Ground current protection may not work if you isolate the computer from ground.

EDIT just one thought. Are we talking about a single frequency hum - or a low level whine made up of lots of digital noise? Some computers cannot provide enough USB current - Focusrite Scarlett that my colleague had would make horrible noises on his computer, and touching the case or the mixer would change the tone of the hum. Plugging it into a mains powered USB hub cured it totally!
 
IM located in europe, 220v 50hz. i have ground in my plugs, sockets ect, that would not solve my house electtry ;)
the sound is exactly the same https://www.youtube.com/watch?v=o7yHYAuMP8A
as i tell- pluging in to grounded socked reduces the noise, but not cures it, without ground the noise is the same as the youtube video given. I just thought its 2016-17 now, maybe there is a cure for this already.. i m think of some sort of usb filter-isolator. cause data via usb is digital, just noise witch comes impacts the analog audio quality on my dac 3.5mm jack mm (witch is unbalanced). So if i can unplug the laptops power suply and there is no hum, so it means there is a way to filter that noise it should be. But im not certain where to ask about it either audio forums, or electricity - radio electronic forums, english is not my main language, so sory for some incorect word sequence..
 
rob aylestone said:
Laptop power supplies are notoriously awful whenever audio connections are made. The MAC people laugh at the PC people because you can get perfectly fine audio from MACs by jus connecting a mega PA to the headphone socket. Most but not all PCs suffer badly from their switch mode power supplies. Dell are probably the worst ones - and some have blamed their ID system that tells the computer if it is a genuine Dell PSU. While non-Dell PSUs often generate a message "This power supply cannot charge the battery on this laptop" however, you might find that an alternate PSU does not produce the hum. Most laptops have modest requirements from a PSU - adequate current and the right voltage. Well worth trying a different one? If you are using a mains power computer and can't do this, then the only real solution would be to source an autotransformer - it's a simple but quite heavy device that has a transformer with two windings, so it produces full mains voltage on the secondary, but it is floating and not normally referenced to ground. Using one, you then ground the computer and all your audio equipment to the real ground in your space. There are some implications with any specific protection you have. Ground current protection may not work if you isolate the computer from ground.

EDIT just one thought. Are we talking about a single frequency hum - or a low level whine made up of lots of digital noise? Some computers cannot provide enough USB current - Focusrite Scarlett that my colleague had would make horrible noises on his computer, and touching the case or the mixer would change the tone of the hum. Plugging it into a mains powered USB hub cured it totally!
Click to expand...
its a single frequency humm with harmonics, its not that chirping noise i have heard otheres have from faulty psu from pc. Its a Humming as i find this word in english describes it best. I have tryed phone charger, and used this to power my dac, it gives humming louder, and if i touch grounding its no change. Havent tried usb hub with external power suply. is it different than phone charger ?
 
What is the brand and model of the gaming headset and does the mic plug have a TRS (tip-ring-sleeve) and not a TRRS (tip-ring-ring-sleeve). The jack on the AG-06 supplies 'plugin power' for the mic and uses a TRS type jack. It may not like a TRRS plug if that is what is on the mic cord.

You don't get the hum with a balanced mic, so that does point to the unbalanced connection the 3.5mm mic as you had mentioned. Again I think the cable of the mic is acting like an antenna to pick up the AC floating around the room. When the laptop or desktop is plugged into the wall outlet it sort of creates a ground loop through the air.
 
yamaha ag06 and kingston hyperx cloud 1 headset. im thinking that if im touching my headsets cable, the noise is increasing, if i fold the cable its also noise increase. so its kinda some sort of antena, but i did went to the audio shop, where i have bought it and there we pluged in to pc, there is no problem no humm..
 
A few more things....
- Did you install the USB drivers for the AG06 mixer?
- Any florescent type lighting (CFL's) in the room or anything else nearby that can be turned off to see if the noise changes.
- The mic should be able to be plugged directly into the mic jack on the laptop or desktop. See how that sounds.
- Found this in a Google search > https://linustechtips.com/main/topi...ng-constant-buzzing-for-others-in-voice-chat/

I rerecorded your video and 'normalized' the dead spots (attached mp3). A little bit of fundamental with harmonics or other hash. That's nasty :(
 

Attachments

arcaxis said:
A few more things....
- Did you install the USB drivers for the AG06 mixer?
- Any florescent type lighting (CFL's) in the room or anything else nearby that can be turned off to see if the noise changes.
- The mic should be able to be plugged directly into the mic jack on the laptop or desktop. See how that sounds.
- Found this in a Google search > https://linustechtips.com/main/topi...ng-constant-buzzing-for-others-in-voice-chat/

I rerecorded your video and 'normalized' the dead spots (attached mp3). A little bit of fundamental with harmonics or other hash. That's nasty :(
Click to expand...

Light on of, any other device power on of, is not affecting humming. The pc mic and line in are also inffected with this dirty power, so i cant use them, its realtec integrated sound board on a z170 motherboard. That was the reason i buy this external dac, and it works well for me, exept this damn 3.5mm unbalanced jack :)

Ofc i have installed ag06 drivers, headset is nothing to do here, i have other headsets, same noise, actualy you just plug anything 3.5mm jack like an extension cable -you'll get noise. As i understand the noise is caried via usb power, and not via usb data. Must find a way to filter this...
 
"then the only real solution would be to source an autotransformer" No Rob, you mean a double wound mains isolation transformer and he should not get one of those either as I shall explain in a mo'.

An Auto Transformer DOES NOT isolate the supply and is used to step up or down a supply, e.g. UK to US.

An iso-traff can be useful where there is a floating supply since is allows the neutral secondary to be earthed without endangering other users on the power utility. BUT! such a transformer MUST be installed and wired by a competent sparks who understands the reasons and systems. The isolated supply will NOT be protected by the primary side breakers.

In the US I understand many studios use "balanced" power from a centre tapped transformer? This is excellent at reducing hum but also carries safety concerns. A blown secondary fuse can still leave a "leg" live ref ground. Bad enough for 55V (US) far more lethal for 110V in UK.

Leave all messings with the mains to the professionals and finding one with "studio/audio" nonce can be tricky!

The laptop PSU issue is caused because some (most?) makers carry the mains earth through to the DC side of the charger. There is no need to do this IF the charger is made as a Class ll double insulated device, these do exist but can be hard to find.

In the OP's situation it would seem he has UK style mains and so the only solution might be the USB ground isolator. Never tried one so cannot comment. N.B. Whilst a mains test plug is useful nay, vital for itinerant recordists/musicians, for the HOME get a lekky in to check the earth resistance.

Dave.
 
poisas said:
I just saw this video https://m.youtube.com/watch?v=DTbOEi0aF0U could this solve my issue? It cost only 10euro.
Click to expand...

Your mic needs 'plugin power' which the mixer does provide. A device like that may or may not block the plugin power from getting to the mic. Don't really know unless you try it. I would have doubts that it might work to suppress noise with the mic even if the mic did work.

You had mentioned an XLR/balanced mic didn't give the problem. Any compelling reason not to use an XLR type mic? You would likely have much better quality/clarity in the sound than the headset.

You had mentioned earlier the interface was tried in the shop and didn't have the noise, but when tried at nearby friends houses it did. Are the places that had the noise possibly on the same supply that supplies your house (same feeder/transformer). Has there been any flickering of lights randomly? Loose or open connections at the transformer neutral or grounding in the supply feeder could perhaps be related to the problem and as Dave suggested perhaps your power supply company could take a look.
 
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