[Gaap]

I'm a long time lurker to head-fi but first time poster and would be terribly happy if I could have some suggestions for my problem.
 
I recently bought a Harmony Design Ear 90 headphone amp to drive my HD650 and Grado SR60e. For a while I have been using only the Dragonfly from my tower computer, Macbook pro and Iphone.
 
Having set up my amp on my computer desk and connecting it to the Dragonfly from PC (Gigabyte motherboard) I noticed quite irritating and highly noticeably noise coming and going with short intervals at all levels. This is not noticeable when using only the Dragonfly (from the same usb bus) powering any of the headphones. Nor is it noticeable when I connect my Macbook (with or without charger from the same wall socket) -> DF -> Harmony Design Ear 90, or using the iphone as a source. I live in an old building with old and bad electrics and that it seems like my macbook doesn't have this problem and is better shielded, but I would like to continue using my PC for my listening. There might have been some improvement (it is still there though) when I tried using a cheap externally powered usb bus to power the Dragonfly. 
 
Do you have any suggestions what I could try out? Trying out Audioquest jitterbug or anything similar? 

 

[Mython]

  I'm a long time lurker to head-fi but first time poster and would be terribly happy if I could have some suggestions for my problem.
 
I recently bought a Harmony Design Ear 90 headphone amp to drive my HD650 and Grado SR60e. For a while I have been using only the Dragonfly from my tower computer, Macbook pro and Iphone.
 
Having set up my amp on my computer desk and connecting it to the Dragonfly from PC (Gigabyte motherboard) I noticed quite irritating and highly noticeably noise coming and going with short intervals at all levels. This is not noticeable when using only the Dragonfly (from the same usb bus) powering any of the headphones. Nor is it noticeable when I connect my Macbook (with or without charger from the same wall socket) -> DF -> Harmony Design Ear 90, or using the iphone as a source. I live in an old building with old and bad electrics and that it seems like my macbook doesn't have this problem and is better shielded, but I would like to continue using my PC for my listening. There might have been some improvement (it is still there though) when I tried using a cheap externally powered usb bus to power the Dragonfly. 
 
Do you have any suggestions what I could try out? Trying out Audioquest jitterbug or anything similar? 

 
 
Yes, you can try a Jitterbug, but you could also try a cheap ferrite core/choke around the input or output leads of the Dragonfly, to reduce RFI from leaking into the headphone amp.
 
It's dirt-cheap to give the ferrite core a try, so you have very little to lose by giving it a go:
 
www.amazon.com/Bluecell-Magnetic-Ferrite-Suppressor-diameter/dp/B00MFCLW58
 
check to find a core with the closest fit to the thickness/diameter of your cable(s). The ones linked above are 5mm, but there are smaller and larger available, if you need them, instead.

 

[Gaap]

Thanks Mython for your suggestion I will check this out! There seem to be few dealers shipping those small things to Sweden and those who do will charge me almost 30 USD for it so I am trying to finding out under what name they go under in Swedish hehe. 

 

[Mython]

  Thanks Mython for your suggestion I will check this out! There seem to be few dealers shipping those small things to Sweden and those who do will charge me almost 30 USD for it so I am trying to finding out under what name they go under in Swedish hehe. 

 
 
You can also find them fitted to many ordinary USB cables. Sometimes they are permanently attached to the PVC sleeve, but sometimes they are just clipped-on, so you might get lucky and be able to find one and un-clip it from the cable, to clip onto your cable.
 
But I'm sure you can buy ferrite cores somewhere in Sweden - I'm certain of it.

 

[Gaap]

   
 
You can also find them fitted to many ordinary USB cables. Sometimes they are permanently attached to the PVC sleeve, but sometimes they are just clipped-on, so you might get lucky and be able to find one and un-clip it from the cable, to clip onto your cable.
 
But I'm sure you can buy ferrite cores somewhere in Sweden - I'm certain of it.

Yes, it would be strange if I couldn't buy these here, however I can't seem to understand what they are called here. But I will go to a electronics dealer with the link from amazon when I have the time, thanks again! Lets see how it goes. 

 

[viivo]

Just so you know why when it doesn't work, chokes were designed and are used to prevent outgoing interference. They are for the benefit of people around you so they don't pick up your noise. They do nothing to any incoming signal and certainly won't magically clean up a noisy signal from onboard audio.

It sounds like a ground loop issue, for which there are a few solutions. Hum eliminators and the like are the simplest but can be relatively expensive (starting at around $50) but they provide an actual positive effect.

 

[Gaap]

Just so you know why when it doesn't work, chokes were designed and are used to prevent outgoing interference. They are for the benefit of people around you so they don't pick up your noise. They do nothing to any incoming signal and certainly won't magically clean up a noisy signal from onboard audio.

It sounds like a ground loop issue, for which there are a few solutions. Hum eliminators and the like are the simplest but can be relatively expensive (starting at around $50) but they provide an actual positive effect.

So where would I put a hum eliminator in that case? The issue is on the motherboard of the PC as it works well with laptops connected to the same wall socket. 

 

[Gaap]

Okay, so I left this problem unsolved, decided to use the Dragonfly for strictly portable use and bought myself a Arcam dac with optical inputs instead. Thanks for the suggestions though! 

 

[Kodhifi]

You don't need a jitterbug or RF chokes. Your problem is 2 grounds. Have you ever wondered why all the electrical power in an automobile is positive and only the bare metal of the car provides negative? It's because if you run positive and negative to multiple locations, the negative acts like a radio antenna, picking up all kinds of interference and alternator noise. 
 
The same is true of a USB DAC getting USB positive and negative, and then connecting to a headphone amp which has it's own positive and negative. The result is tck tck tck beeeep tktktktktktk   
 
You need a $5 ground loop isolator purchasable at any car audio store, best buy, amazon.com, you name it. It sends the signal but breaks electrical ground and puts an end to hum and noise from different grounds in an audio system.