Grounding issue with HiFiman Edition XV

[antcollinet]

but when i unplugged the amp and dac from the power socket, hum is there. Only when I unplugged it from laptop usb port, it goes away

Hang on - where is the hum coming from if it is still there with amp and dac disconnected. Are you talking about hum coming from a device - rather than from your 'phones?

In any case - if the hum only comes when you plug in the USB cable - using TOSlink will eliminate it because then there is no electrical connection between PC and DAC.

 

[winsome]

apologies, let make it clearer. I unplugged the dac and amp from power socket entirely, hum still there. When I unplugged the usb cable from laptop, it goes away, even when I plug Amp/dac to the electric socket.

Strange thing is that at the state of the amp/dac unplugged, when I touch the casing, hum goes away even when usb is plugged

 

[antcollinet]

apologies, let make it clearer. I unplugged the dac and amp from power socket entirely, hum still there. When I unplugged the usb cable from laptop, it goes away, even when I plug Amp/dac to the electric socket.

Strange thing is that at the state of the amp/dac unplugged, when I touch the casing, hum goes away even when usb is plugged

But still my question - if your amp is unplugged, what is humming. Your headphones? Your Amp itself? your dac? your PC? (obviously if your amp is unplugged it can't be driving hum into your headphones - hence my confusion)

It might be helpful if you sketch your system - what is plugged into what, by what type of interconnect, - where.

 

[AnalogSteph]

It's pretty clear that there is mains leakage from the laptop power supply traveling via headphone cable ground return to listener to ground in this case.

The only odd part is that I would expect big planars to be too insensitive and fairly well-insulated from the listener to clearly show this effect. I've only experienced it on in-ears before. Mind you, perhaps the construction of planar drivers + ear distance results in a bunch of capacitive coupling here, who knows.

 

[winsome]

But still my question - if your amp is unplugged, what is humming. Your headphones? Your Amp itself? your dac? your PC? (obviously if your amp is unplugged it can't be driving hum into your headphones - hence my confusion)

It might be helpful if you sketch your system - what is plugged into what, by what type of interconnect, - where.

sorry for the late reply. when i unplugged either amp or DAC, the headphone is still humming.

System wise is simple, PC to DAC to amp. Dac is smsl D400ES, amp is gustard. Balanced cable between DAC and amp. USB cable is wireworld ultraviolet. Stock power cable from both amp and DAC. Headphone like i mentioned above is Hifiman HE600

Now the even more interesting update : I'm bought some cheap aftermarket XLR termination balance cable, the hum is even more evident and even audible when song is playing at right channel. The system is located on the right hand side near where I sit in front of computer on a rack. HOWEVER, when I look/tilt my head to right side, hum goes away. And this hum goes on and off, sometimes its there, sometime not.

PLUS, I just got a new headphone, ZMF Atrium, no hum whatsoever. I already bought a neutrik XLR and looking to build a new cable for the HE600

Additionally this hum also happens on my son setup. His is Aune N7D with Hifiman Ananda Unveiled. If this is a QC issue then I strike a huge jackpot for a problems with both headphones? I wont be totally suprised knowing QC of hifiman or I probably need to go to sorcery/voodo forums than audio with this.

 

[winsome]

Folks, just got a new set of cable, with a decent IC ,neutrik xlr and oyaide 3.5mm - but its a TRRS ,not TRS. Have read there are compatible and can be use for audio only. The hum or buzzing still there. Still the same symptom as described above. To add, hum or buzzing sound appear after some time playing, not immediately.

I really want to like the HE600, I believe its very close or maybe equally good as Atrium. But with this hum, its just unacceptable. I started to think its the headphone now that's the cuplrit

Can someone chime in and give explanation on what is going on? Thank you

 

[solderdude]

Can someone chime in and give explanation on what is going on? Thank you

There probably is a large amount of RF being picked up by the headphone cable and the amp it is connected to is probably not well designed in this aspect ?
Possibly some 10nF capacitors directly at the output or perhaps even a clamp-on ferrite with the cable looped 3x trough it as closes as possible to the headphone out of the amplifier may cure the issue. No guarantees.

Try to borrow another amp somewhere and see if the problem goes away.

 

[winsome]

thank you. But if that is the explanation how come it didnt happen to the atrium? Because its less sensitive? The stock cable on the atrium have no ferrite

 

[Dazeistaken]

I have a funny problem with my set up and it only occurs with my HiFiman Edition XV headphones. No other, including sensitive IEMs. Tried changing cable. Also, I have moved and it occurs in both my new place and the old. The sockets are all ungrounded from the wall.

I hear a hum but whenever I put my hand on my Matrix Element-i DAC streamer or any other equipment it disappears. There has to be some kind of ground potential difference occuring.

The Element-i has a grounding post. Would a grounding box connected to this post solve my issue?

There's also an iFi device that you put into a socket that creates "virtual ground". Any idea if this works?

One idea I had was to use a wire from the Element-i and just connect it simply to a radiator. Stupid idea?

I am willing to pay around 60 USD for a solution that really works.

Oh, I sent the headphones to the distributor but they couldn't find a problem with them so they sent them back without any fix.

I had the same problem with mine. I found out it was caused by my ears touching the metal mesh inside the cups. The buzzing stopped immediately when I moved the cups slightly away from my ears. I tested this by placing the foam discs from my HD600 inside as an insulator, and the noise disappeared completely. It seems the human body acts as an antenna, and the contact with the mesh creates a ground loop. I ended up returning them because such a design flaw is unacceptable at this price point.

 

[Norville]

I had the same problem with mine. I found out it was caused by my ears touching the metal mesh inside the cups. The buzzing stopped immediately when I moved the cups slightly away from my ears. I tested this by placing the foam discs from my HD600 inside as an insulator, and the noise disappeared completely. It seems the human body acts as an antenna, and the contact with the mesh creates a ground loop. I ended up returning them because such a design flaw is unacceptable at this price point.

That seems to be the case with my pair too, I tested it and yeah, on the right ear-cup especially, it does disappear when my ear stops touching the mesh. I'm happy it isn't a general grounding issue though and in my case I will keep the XV because I love them regardless, it's absolutely not audible when music is and I try not to be so picky when it comes to things like this. Before, I was chasing a dead silent background, now I focus more on things like timbre and general tuning and tonality.

 

[solderdude]

I had the same problem with mine. I found out it was caused by my ears touching the metal mesh inside the cups. The buzzing stopped immediately when I moved the cups slightly away from my ears. I tested this by placing the foam discs from my HD600 inside as an insulator, and the noise disappeared completely. It seems the human body acts as an antenna, and the contact with the mesh creates a ground loop. I ended up returning them because such a design flaw is unacceptable at this price point.

Most likely the - of the driver (sleeve of the 3.5mm connector) is connected directly to the metal enclosure which is in contact with the magnets.
A design oversight.... Hifiman should have used an isolator between the metal enclosure and the sleeve of the headphone connector.
This is due to the enclosure being all metal where most other headphones are plastic or even wood.
When you make a connection with your body a small leakage current from amp/PC or whatever is connected can flow.
That is not an issue by itself as it is too low to be dangerous but when connected to gear that is not well designed that low leakage current can become audible.