Buzz/Hum from Audioquest Dragonfly DAC to Asgard 2 headphone amp

Clipdat
Clipdat Posts: 12,934
edited March 2014 in Troubleshooting
So, I've been using my dragonfly with my powered PC speakers for months now and I've been thrilled with it, zero issues to speak of.

Tonight I tried running it to the new Asgard 2 headphone amp I just purchased (using it low gain mode with 24ohm, 107dB sensitivity headphones), and when I have no music playing, I notice that when the volume knob reaches the 10-11 o'clock position I start to hear a buzz/hum coming through the headphones. It increases as I turn the volume knob up more.

It's not a huge deal for most music, but for songs recorded at lower levels or for quiet passages the background noise can definitely be noticed. Just wondering what I can to do mitigate it, short of a 3 -> 2 prong ground lift adapter on the Asgard 2. Maybe I need something like this?? http://www.musicdirect.com/p-160962-ifi-micro-iusb-power-supply.aspx but honestly for the price of that, I should just get a DAC that supports an optical input.

Just surprised since I thought one of the dragonfly's selling points was that it was a higher quality output than a standard PC soundcard.
Post edited by Clipdat on
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  • Clipdat
    Clipdat Posts: 12,934
    edited March 2014
    I just realized this section is for Polk specific troubleshooting, mods please feel free to move it to another area if needed.
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  • Clipdat
    Clipdat Posts: 12,934
    edited March 2014
    Upon further reading, it sounds like I'm dealing with a typical ground loop hum issue: "If a signal is passed from one to the other via an audio connection with the ground wire intact, this potential difference causes a spurious current through the cables, creating an audible buzz at the AC mains base frequency (50 or 60 Hz) and the harmonics thereof (120 Hz, 240 Hz, and so on), called mains hum. Sometimes, performers remove the grounding pin from the cord connecting an appliance to the power outlet; however, this creates an electrocution risk"
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  • Clipdat
    Clipdat Posts: 12,934
    edited March 2014
    Update: I ordered the Ebtech Hum X and it has completely made the hum/buzz go away! www.amazon.com/Ebtech-Hum-Voltage-Filter/dp/B0002E4YI8/ref=sr_1_1?ie=UTF8&qid=1395112989&sr=8-1
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  • voltz
    voltz Posts: 5,384
    edited March 2014
    Clipdat

    Thanks for info as I had the same problem with a WOO Headphone amp plugged into my "Panamax power line conditioner. I knew I heard this talked about here before. I just started looking for these threads when I found yours. If I plug my amp into the other wall outlet no hum. but its to far away for everyday uses.

    Thanks for the fix :)
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
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  • gudnoyez
    gudnoyez Posts: 8,124
    edited March 2014
    I considered buying a Audioquest Dragon Fly, before I bought my Jd Labs C5 amp. Stupid question on my behalf, the Audioquest is through the USB port on your computer, how does one hook up a headphone amp to it. Curious as I might get a Dragonfly down the road to hook up to the C5 while sitting in front of the PC? The Dragonfly came highly recommended on most of the reviews I have read.
    Home Theater
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    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

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  • Clipdat
    Clipdat Posts: 12,934
    edited March 2014
    voltz: You'll have to report back and let us know if the Hum X also worked for you.

    gudnoyez: Technically, per Audioquest's documentation, the Dragonfly has it's own "built in" headphone amplifier - meaning that you can drive a pair of headphones directly from it. What I did is just run a 3.5mm stereo to L + R RCA cable from the Dragonfly to my Asgard 2's input. Then I just set the application's volume, and the Dragonfly's volume (the main volume slider in Windows) both to 100% so I know I'm getting the full signal output.

    As a somewhat funny sidenote, I'm just using a cheap Monster branded 3.5mm to RCA cable right now and I noticed that the channels are reversed on it. I found this out by playing with the balance slider in Winamp. So for now I've just swapped the red and the white on the input of the Asgard 2 but it looks like I'll probably be purchasing an Audioquest cable to replace it. Monster can't do anything right! :)
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  • voltz
    voltz Posts: 5,384
    edited March 2014
    Got it in the mail today and it did the trick! No hum at all :)
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
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  • Clipdat
    Clipdat Posts: 12,934
    edited March 2014
    Nice! Glad to hear it worked out for you! :D
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  • EndersShadow
    EndersShadow Posts: 17,590
    edited March 2014
    voltz wrote: »
    Got it in the mail today and it did the trick! No hum at all :)

    So what your saying is that cables do make a difference..

    :smile:
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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