Shielded Ethernet cable suggestions to cure ground loop like hum

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  • stangman67
    stangman67 Posts: 2,185
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    I feel for you! I went through the same thing with him after I put my VPI table in the loop and finally traced it down to a dimmer switch. Was definitely a rage inducing troubleshooting process.

    Good luck with figuring it out!
    2 Channel in my home attic/bar/man cave

    2 Channel Focal Kanta 3 I Modwright SWL9.0 Anniversary Pre I Modwright PH9.0X I Modwright KWA-150SE I VPI Prime Signature w/ Soundsmith Zephyr MIMC I Lumin U2 Mini I North Star Designs Intenso DAC I Audience OHNO ICs/Audience Furutech FP-S55N and FP-S032N Power Cables/Acoustic Zen Satori I Isotek Sirius
  • heiney9
    heiney9 Posts: 25,080
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    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
  • ALL212
    ALL212 Posts: 1,556
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    So…

    If that Ethernet surge plugged the words are remembered, no hum.

    If you ground the green wire does it forget the words?

    STP - absolutely cat 5e or better but STP. Regardless of this issue use STP if the budget allows. Mono price has cat 7 and 8 and if you don’t care about color you can sometimes get good prices.

    Not all pairs in cat wiring are used for TCP/ip and it’s not impossible that the wire is fine but your end point devices aren’t quite wired under the full standards correctly.
    Aaron
    Enabler Extraordinaire
  • heiney9
    heiney9 Posts: 25,080
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    A2 - This is the current cable I'm using......I was under the impression it was STP?

    https://www.amazon.com/gp/product/B00HEM5YJE/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
  • ALL212
    ALL212 Posts: 1,556
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    Yep - it states shielded and the connections appear to be metal.

    So you have good cable. What also needs support for STP are the endpoints. The 8 wires don’t provide the shielded ground, the connectors/ connections do via the foil or mesh around the wires.

    This isn’t a definitive step to be rid of the humm but it does mean you’ve got a good Ethernet wire.

    There are other threads about using fiber and it’s not particularly expensive to try a basic setup. If this a ground loop issue a fiber drop should kill that.

    Roughly:

    Good short Ethernet cable to a converter. Converter outputs are fiber (fiber patch cable - probably about $1 / foot) other end fiber to converter and good short Ethernet to the device. STP not required.

    $60 some odd + fiber patch cable and a couple of short Ethernet cables for troubleshooting. Then go nuts on parts if this works.



    https://www.amazon.com/Gigabit-SFP-Dual-Transceiver-1000Base-Tx/dp/B099JF9KJD/ref=mp_s_a_1_1_sspa?crid=3HYEJ6O0QIB3S&keywords=fiber+to+ethernet+converter&qid=1675627266&sprefix=fiber+to+ethrr,aps,101&sr=8-1-spons&ufe=app_do:amzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyT1RZMVYzN09aS1IxJmVuY3J5cHRlZElkPUEwODU0MjQ5MkwzUjRDSjQ4WFlCMCZlbmNyeXB0ZWRBZElkPUEwNTg0NDIxMjBaODRQMUIwVk1YUCZ3aWRnZXROYW1lPXNwX3Bob25lX3NlYXJjaF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

    Aaron
    Enabler Extraordinaire
  • SCompRacer
    SCompRacer Posts: 8,352
    edited February 2023
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    Like this. (Aaron introduced me to this last year. Thanks Aaron!). IIRC Ed the SRT king has them too. Eventually I'll mount them on screen behind rack. Most folks will use the wall wart on the 'dirty' side FMC and use a good linear PS for the 'clean' side FMC. There are single SFP and multi-mode (dual) SFP modules. These are dual or duplex LC to LC fiber. Just ensure you buy the correct fiber cable to match the SFP modules you go with. They were out of single SFP's when I purchased mine.

    rxol9lp67p2i.jpg

    This PS was ~$90 on Amazon. Uses Vishay BC caps. While it has two 5v outputs, I don't connect both modules with PS or I lose galvanic isolation. Some suggest connecting dirty side FMC to different outlet.
    https://www.amazon.com/dp/B07T44S4MV?psc=1&ref=ppx_yo2ov_dt_b_product_details

    7tfi5vyvam7o.jpg

    My stuff... ~ $167.
    Two SFP's. Available as single or multi (dual). These are the ones Small Green Computer uses/suggests. Their kit is ~$350 with their PS.
    https://www.amazon.com/dp/B003CFATYM?ref=ppx_yo2ov_dt_b_product_details&th=1
    Short fiber (you have to observe a gradual bend radius so you don't damage fiber).
    https://www.amazon.com/dp/B07YLCQLGK?psc=1&ref=ppx_yo2ov_dt_b_product_details
    Two of these.
    https://www.amazon.com/dp/B08Z7BZG5K?psc=1&ref=ppx_yo2ov_dt_b_product_details
    The PS.
    https://www.amazon.com/dp/B07T44S4MV?psc=1&ref=ppx_yo2ov_dt_b_product_details

    I already had Cat STP patch cords. My wall jacks are shielded as well.

    afizxhkz1hcg.jpg
    Post edited by SCompRacer on
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
  • msg
    msg Posts: 9,446
    edited February 2023
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    Cool stuff, Rich! Might check out one of those power supplies to use with the SBT.
    ALL212 wrote: »
    Yep - it states shielded and the connections appear to be metal.

    So you have good cable. What also needs support for STP are the endpoints. The 8 wires don’t provide the shielded ground, the connectors/ connections do via the foil or mesh around the wires.

    This isn’t a definitive step to be rid of the hum but it does mean you’ve got a good Ethernet wire.

    There are other threads about using fiber and it’s not particularly expensive to try a basic setup. If this a ground loop issue a fiber drop should kill that.

    Roughly:
    Good short Ethernet cable to a converter. Converter outputs are fiber (fiber patch cable - probably about $1 / foot) other end fiber to converter and good short Ethernet to the device. STP not required.

    $60 some odd + fiber patch cable and a couple of short Ethernet cables for troubleshooting. Then go nuts on parts if this works.
    Ern, question I had earlier in the thread was re: whether there were metal shields on the original ethernet cable. There was a lot of activity so it may have been missed.

    If no shielded conns on the first cable, then the noise is transmitting across the signal pairs, yes.

    If there were shielded connectors on that first cable as well, then it makes sense to try to either defeat the shield on the connector on the far side, or remove it altogether. Same thing Rich mentioned with the use of the Kapton tape on that USB connection, and also mentioned by @Groundrod speaking specifically to the ethernet connector shields.

    Of course if not yet tested, the other easiest option would be to use a regular ethernet cable with no shielding if one on hand. I think it's unlikely that this noise is being picked up along the way. Seems more likely it's being transmitted from the source.

    Also - I may have missed this - but, @heiney9, with the ethernet still in place and hum present on the speakers, did you ever disconnect your coax from your modem to see whether the hum dropped away?

    There were a couple of key questions here that I'm not sure were answered, but I may have missed them.

    That fiber conversion is a surefire fix, @ALL212 @SCompRacer, and looks to be nicely affordable, as well, not to mention, a pretty friggin' neat idea. Interesting upgrade. I like that power supply. I think I'm gonna try one of those for my SBT.
    I disabled signatures.
  • msg
    msg Posts: 9,446
    edited February 2023
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    I know this isn't the same situation, since it is a USB digital cable in this case, but before I got the SBT and I used to connect up to my ifi nano idsd DAC from my computer via USB cable, I used to get 8kHz packet noise spikes that was very annoying and because I was so attuned to hearing it, it destroyed my enjoyment of music (my guests barely heard it, except quiet between songs). It got worse the higher the amplification. Powering the DAC separately and not using the USB for the power did not cure the problem. The noise was coming through the digital wires of the USB because the computer digital output was contaminated with it, for whatever reason.

    So digital wires can definitely carry or pickup an analog noise signal, despite the 1s and 0s thing seeming to proclude that. The quality of the source is a factor.
    @SCompRacer Rich mentioned this earlier in the thread, but the USB noise situation is very similar to Brock's ethernet situation. I fought through that USB issue as well.

    I learned that there are two ways USB audio can be hosed up:
    1. If your DAC is running off the same USB bus as other USB devices, which is quite likely, you are passing audio on the same USB bus as other USB traffic. A spinning external hard drive polling and parking will present as noise in your audio. So will use of a mouse, and it's an extremely annoying sound.
    2. You may also notice that keyboard and mouse control becomes erratic and unreliable while playing audio over USB.

    The fix for me was to install a dedicated USB 2.0 card for connection to a USB DAC to remove the USB bus noise. I didn't have a compound issue with the power noise, but it happens. There are special cables you can buy that separate the signal and power paths to remove noise and purify the signal path. iFi makes one, and there's also some guy out there who was making something. Just checked my notes - the "USB Disruptor".

    @SCompRacer - do you still have that fancy USB card?!?

    I disabled signatures.
  • msg
    msg Posts: 9,446
    edited February 2023
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    Disregard my posts above - you answered your question here with this post where you mention using the Tripp-Lite device:
    https://forum.polkaudio.com/discussion/comment/2713233/#Comment_2713233

    By using Tripp-lite inline device, presuming you used a regular ethernet cable in one of the ends of it, you removed the shielding on the cable connectors from the path, which is likely what's been transmitting the hum across the connection path.
    I disabled signatures.
  • SCompRacer
    SCompRacer Posts: 8,352
    edited February 2023
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    msg wrote: »

    @SCompRacer - do you still have that fancy USB card?!?

    Yes, I still have the discontinued Sonore Audiobyte USB to i2s interface in a Twisted Pear BIII 9038Pro DAC, TP Mercury I/V stage. The Audiobyte has USB isolation and topped out at Native DSD128. It also has a switchable on/off oversample filter for PCM, 384kHz. This is parked for now as I have a Gustard R26 DAC with Singxer SU-6 DDC. The R26 will do 768kHz/DSD512.

    I also have an Amanero USB to i2s module with Twisted Pear Hermes USB isolator and TP Cronus reclocker.

    6h2s4amqsd1t.jpg
    iinr1f7ofudc.jpg
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *