Help needed!Mains noise in all my usb DACs, it stops when i touch some metalic part with my fingers.

[CerealKiller]

Hi dear comunity, I'm having this problem with my setup wich i I cant seem to find a way around it.

Mains noise leaks to every dac I own when conected via USB, it hapens in standalone dacs, as my topping D10 and DX3pro and also through my audio interfaces, bheringer euphoria and Motu M4.

I know its mains noise because the tone of it its exactly 50hz, wich happens to be the frequency of the grid where I live. (220V-50Hz)

Now, when i touch the metal case of the dac with my finguers, or even the metal case of my laptop it stops. Clearly i become the ground.

What is this phonemena called? Is this mains noise? Ground loops?

And most important, how do I stop it?!

Pluging everthing to antoher power outlet doesent make any diference whatsoever,
It is related to the usb conection because if conect my dx3 pro to my desktop pc via toslink theres no noise.

Sadly my audio recording interfaces do not have toslink, those are usb conection only.

I apreciate any help u guys can give me,

Cheers!

 

[gfx_1]

Does the poweroutlet have an earth connector? (third pin)
Are there devices connected which need an earth? e.g. switching powersupplies like desktop computers.
Not all laptop PSU's have an earth connector so you can feel a slight sensation from the metal parts of the casing (e.g surface pro 4)

I connected the earth screw from the phono input on the amplifier with a wire to earth to ground it.
Everything connected to it via cinch cables is then on the same level.
Not so much for a hum but for the little switching psu the amp uses for standby.

 

[Harmonie]

Hi dear comunity, I'm having this problem with my setup wich i I cant seem to find a way around it.

Mains noise leaks to every dac I own when conected via USB, it hapens in standalone dacs, as my topping D10 and DX3pro and also through my audio interfaces, bheringer euphoria and Motu M4.

I know its mains noise because the tone of it its exactly 50hz, wich happens to be the frequency of the grid where I live. (220V-50Hz)

Now, when i touch the metal case of the dac with my finguers, or even the metal case of my laptop it stops. Clearly i become the ground.

You just found the solution yourself.
If it stops because you are the "ground", you should find a better "ground".
Obviously your installation lacks a well grounded mains.

 

[McFly]

Pluging everthing to antoher power outlet doesent make any diference whatsoever,

Can you run an extension lead from the other side of the house/apartment (NOT just the other side of the room or the next socket over) and plug everything in a multi-box, INCLUDING the PC, to it and report back? Make sure all leads, multiboxes and the PC have a ground pin.

 

[CerealKiller]

Does the poweroutlet have an earth connector? (third pin)
Are there devices connected which need an earth? e.g. switching powersupplies like desktop computers.
Not all laptop PSU's have an earth connector so you can feel a slight sensation from the metal parts of the casing (e.g surface pro 4)

I connected the earth screw from the phono input on the amplifier with a wire to earth to ground it.
Everything connected to it via cinch cables is then on the same level.
Not so much for a hum but for the little switching psu the amp uses for standby.

Yes, every mains cable has the third pin, and outlets have the ground wiring present to, i opened them and checked, Im not to fond on the building electryc instalation beeing corectly earthed thoug... and I assum that something only a trained electrician should be checking. Oh and my laptop metal case definity "feels" like it is vibrating to the humm noise.

 

[CerealKiller]

Can you run an extension lead from the other side of the house/apartment (NOT just the other side of the room or the next socket over) and plug everything in a multi-box, INCLUDING the PC, to it and report back? Make sure all leads, multiboxes and the PC have a ground pin.

Yes i can, in case it solves the problem, this will prove if the earth wiring of that room is defective right? And in case it doesnt solve it, proves the whole appartment earth wiring beeing conected to, well not a good earth rigth?

 

[CerealKiller]

You just found the solution yourself.
If it stops because you are the "ground", you should find a better "ground".
Obviously your installation lacks a well grounded mains.

Ok I guess the better option would be to have it revised by a certified electrician then. Thanks!

 

[Godataloss]

One of these might help- https://www.allo.com/sparky/nirvana-smps.html

 

[AnalogSteph]

Yes, every mains cable has the third pin, and outlets have the ground wiring present to, i opened them and checked, Im not to fond on the building electryc instalation beeing corectly earthed thoug... and I assum that something only a trained electrician should be checking. Oh and my laptop metal case definity "feels" like it is vibrating to the humm noise.

While it does sound like you ought to have a ground connection somewhere but clearly don't, please list your computer hardware and what sort of mains connection they have. If any of the computer or monitor have a 3-pin IEC power connection, the setup should be grounded through that and draining mains leakage there. If it isn't anyway, you clearly do need to get the mains wiring checked over. It's not OK to have grounded outlets with the PE just floating in thin air. What country are you located in?

 

[Deleted member 46664]

Hi dear comunity, I'm having this problem with my setup wich i I cant seem to find a way around it.

Mains noise leaks to every dac I own when conected via USB, it hapens in standalone dacs, as my topping D10 and DX3pro and also through my audio interfaces, bheringer euphoria and Motu M4.

I know its mains noise because the tone of it its exactly 50hz, wich happens to be the frequency of the grid where I live. (220V-50Hz)

First ... this sounds like your home wiring is either damaged or incorrect. The hum tells me you have a floating ground somewhere. Clearly this is not something to mess with on your own. You should bring in an electrician and have your outlets checked... I'm betting they're either wired wrong or not grounded.