How to get rid of that Hum....

Polkitup2
Polkitup2 Posts: 1,622
edited February 2012 in Basic Hookup/Wiring Questions
Numerous times over the life of my audio system I have been plagued with a ground loop hum. In the past I have been able to fix the issue by using a Jensen ground isolator on the Cable TV. Recently I changed speakers and amps and probably a few other things which resulted in a ground loop hum so bad through my speakers that I could no longer stand to even use my HT. My 2 channel system is integrated with my HT via a pre-amp with HT bypass inputs and was not affected by the ground loop. I isolated the problem to the use of the HT bypass between AVR and pre-amp. I tried everything that I had ever heard of to remove the hum including, plugging all components into one dedicated circuit, lifting the ground on individual and all components, taking everything apart and re-assembling one piece and a time to find the problem piece, disconnecting cable and ethernet, replacing the AVT, pre-amp, and amps with different components etc. Nothing would get rid of the hum. So I tried this:

http://www.amazon.com/Monster-MPC-ISM-201-XLN/dp/B0009RWKKM :evil:

Which did nothing or very little to reduce the hum. And then I tried this:

http://www.jensen-transformers.com/ci2rr.html :biggrin:

This removed 95% of the hum. I can only hear the hum with my ear a few inches from the speaker. I still don't get how I can have a ground loop with all components connected to the same outlet with the ground lifted, but for now I am happy with the results I got and just wanted to plug another great Jensen product.
Post edited by Polkitup2 on
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Comments

  • steveinaz
    steveinaz Posts: 19,538
    edited February 2012
    Sometimes integrating 3-prong ac plug equip with 2-prong ac stuff will cause a hum as well. Their are quite a few DVD/BluRay players that have 2-prong ac plugs. Why this, I don't know...

    You can buy grounding stations (for stubborn hum that just won't go away) where each piece of equipment is chasis-grounded to the station.
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Shop Spkrs: Elac Debut 2.0 B5.2
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  • brgman
    brgman Posts: 2,859
    edited February 2012
    Where did you place the jensen in the system?
    Between what unit(s)?
    Main Rig-Realistic AM/FM Record player 8 track boasting 4 WPC

    Backup Rig-2 CH-Rogue Audio Zeus w/Factory Special Dark Mods,Joule-Electra 300ME Platinum Preamp,OPPO-105 w/Modwright Tube Mod, Auralic Aries G2.1,Polk 2.3TL,3.1TL's,Dreadnought,RTA-15TL's,1C's All Fully Modded,2xRTA-12c's ,Benchmark DAC3 HGC,Synology NAS,VPI Scout w/Dynavector DV-20XH and Rogue Audio Ares Phono Preamp,Sony PCM-R500 DAT,HHB-850 Pro CDR,Tascam CC-222SLMKII Cassette/CDR,MIT S3.3 Shotgun Cables,Shunyata Hyra-8,Shunyata and Triode Labs Power Cords

    I’M OFFENDED!!!!
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  • acmf74
    acmf74 Posts: 936
    edited February 2012
    I also had a hum/hiss in my system. I narrowed it down between my AVR and Preamp. I plugged the AVR into the APC H15 and it cleared it up 85% of it. Now it's only audible if I put my ear up to the speakers.
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  • Polkitup2
    Polkitup2 Posts: 1,622
    edited February 2012
    brgman wrote: »
    Where did you place the jensen in the system?
    Between what unit(s)?

    Bewteen AVR front pre-outs and pre-amp HT bypass inputs.
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  • mikehpolk
    mikehpolk Posts: 27
    edited February 2012
    Surely a grounding problem. I had one hum with my last setup and just taped a bit of speaker wire to my amp adn DVD chassies.
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  • leftwinger57
    leftwinger57 Posts: 2,917
    edited February 2012
    I also had a hum that was pretty noticeable and quite annoying.Like you I redid all connections changed to 3 pronge plugs changed outlets and even loosened the ty-raps a bit and also like you I integrated my h/t w my 2 chl so I can get the benefit of i-net radio and the dock out of my avr. The culprit was the HDMI cable going out of the Yamaha which I only use for on screen YPAO and not much else. Needless to say that's gone but ready if needed and the hum is now that lovely sound of pure 200wpc coming through cleanly.I use a Samson 9 outlet surge pro ,whether or not it does anything I don't know.
    2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

    H/T- Toshiba au40" flat- Yamaha RX- V665 avr- YSD-11 Dock- I-Pod- Klipsch #400HD Speaker set-

    Bdrm- Nikko 6065 receiver- JBL -G-200s--Pioneer 305 headphones--Sony CE375-5 disc
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  • luxun54
    luxun54 Posts: 9
    edited February 2012
    I also recently had a nasty hum in the center speaker that I thought might be related to the cable TV box, but I checked everything connected to the Pioneer receiver, and that wasn't it. It turned out that my old iPod mini that was sitting in the Pioneer iPod cradle was causing the hum! It does NOT happen when I use a newer iPod Photo or Classic, only with the iPod Mini. Any idea why this would be?
    Main HT/Music Room: Polk LSi15 front, LSiC center, FXi30 surround speakers, HSU Research VTF-3 MK3 Subwoofer
    Yamaha Aventage RX-A810 A/V Receiver, NAD T-955 power amp
    Nakamichi MB-8 CD Player, JVC XV-S500 DVD Player

    Weekend Home: Polk RT1000i front, CS3 center, OWM3 surround speakers, PSW505 subwoofer
    Pioneer VSX-1017 AV Receiver
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  • leftwinger57
    leftwinger57 Posts: 2,917
    edited February 2012
    Addendum to my first reply,The hum I was getting was not from any bad wireing,wrong style plug or picking up interference from who knows where. I totally dismanteled my self made rack which was constructed of angle iron,L brackets,machine screws w/ lock washers and nuts and wood shelves. now no hum hiss or any unwanted sounds.Looks like I was picking up a gnd through the rack ,but it was based on 3/4 ply on a wood floor so I still do not see from where it came .All I know it's gone and the stack looks ands more importantly sounds better.
    2chl- Adcom GFA- 555-Onkyo P-3150v pre/amp- JVC-QL-A200 tt- Denon 1940 ci cdp- Adcom GFS-6 -Modded '87 SDA 2Bs - Dynamat Ext.- BH-5- X-Overs VR-3, RDO-194 tweeters, Larry's Rings, Speakon/Neutrik I/C- Cherry stain tops Advent Maestros,Ohm model E

    H/T- Toshiba au40" flat- Yamaha RX- V665 avr- YSD-11 Dock- I-Pod- Klipsch #400HD Speaker set-

    Bdrm- Nikko 6065 receiver- JBL -G-200s--Pioneer 305 headphones--Sony CE375-5 disc
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  • mhardy6647
    mhardy6647 Posts: 33,917
    edited February 2012
    a bag of clip leads is always a good investment when troubleshooting hum issues!

    http://www.parts-express.com/pe/showdetl.cfm?Partnumber=360-150&FTR=clip%20leads

    360-150_s.jpg
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