Eliminating hum from ground loops
Bubinga99
Posts: 283
I've got some very audible hum, looks like this at the speaker inputs:
which seems to be due to the audio from my set top box being brought over to my pre-amp, with the loop being completed by a recent new piece of gear (also plugged into a line input on the preamp) with a 3-prong plug.
Anyone ever use one of these Hum-X things:
http://ebtechaudio.com/humxdes.html
and how well did it work out?
They aren't exactly cheap, but if it works...
which seems to be due to the audio from my set top box being brought over to my pre-amp, with the loop being completed by a recent new piece of gear (also plugged into a line input on the preamp) with a 3-prong plug.
Anyone ever use one of these Hum-X things:
http://ebtechaudio.com/humxdes.html
and how well did it work out?
They aren't exactly cheap, but if it works...
Post edited by Bubinga99 on
Comments
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Not sure, but...
What kind of oscilloscope is that? Agilent/HP?polkaudio RT35 Bookshelves
polkaudio 255c-RT Inwalls
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polkaudio XRT12 XM Tuner
polkaudio RM6750 5.1
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When you say "set top box", what do you mean? I ask because I had a ground loop issue with my cable DVR, which caused faint rolling lines to my projector when I was running component video. Had to throw an isolator on the cable line to fix it.Equipment list:
Onkyo TX-NR3010 9.2 AVR
Emotiva XPA-3 amp
Polk RTi70 mains, CSi40 center, RTi38 surrounds, RTi28 rears and heights
SVS 20-39CS+ subwoofer powered by Crown XLS1500
Oppo BDP-93 Blu-ray player
DarbeeVision DVP5000 video processor
Epson 8500UB 1080p projector
Elite Screens Sable 120" CineWhite screen -
Disconnect the Cable line (coax) going to the set-top box and see if that eliminates the hum. It's one of the most common causes of a Ground Loop hum further down the audio chain.____________________
This post is a natural product. The slight variations in spelling and grammar enhance its individual character and beauty and in no way are to be considered flaws or defects.
HT:Onkyo 805, Emotiva XPA-5, Mitsu 52" 1080p DLP / polkaudio RTi12, CSIa6, FXi3, uPro4K
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kuntasensei wrote: »When you say "set top box", what do you mean? I ask because I had a ground loop issue with my cable DVR, which caused faint rolling lines to my projector when I was running component video. Had to throw an isolator on the cable line to fix it.
Parts Express used to have these cable isolators for sale, they work well but slightly attenuate the signal.polkaudio RT35 Bookshelves
polkaudio 255c-RT Inwalls
polkaudio DSWPro550WI
polkaudio XRT12 XM Tuner
polkaudio RM6750 5.1
Front projection, 2 channel, car audio... life is good! -
Coaxial isolator might work too, but has insertion loss and other possible signal quality issues to consider in picking the right one. Guitar Center carries the Hum-x and there's a store near me. I called and they said I can return it if it doesn't work. Reason I think that might work is I temporarily replaced the 3-prong plug with a 2-prong and no more hum.
Scope is an older Tektronix 400MHz 4-channel.
Set top box is just a basic digital cable tuner/demod. RG-6 in, baseband video and audio out. No other functions like DVR. Cable modem is separate. -
Never mind. I'm tired. Goin' to bed now. I've got a date with the pillow.
Carry on..........~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~ -
If it turns out to be your box, run audio via Toslink if possible, this will break the loop.Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Source: Rotel CD14MkII CD Player - Speakers: Elac Debut 2.0 B5.2
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Steve, my preamp is from the Mesozoic era and only has unbalanced RCA connections
The Hum-X...works. -
I use the humX on my DJ gear when I do Karaoke. Everytime I plug in a LCD I get a hum but the HumX stopped it. I also have had different venues where no matter what I did I would get a buz and again HumX helped me.Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's.
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I need to try one of these. My Direct TV HD DVR is causing my problem but I still have it when I use toslink cable but do not if I remove the sat coax from the DVR.
It would be nice to be able to put the ground pins back in on my PS audio power cables.Speakers: SDA-1C (most all the goodies)
Preamp: Joule Electra LA-150 MKII SE
Amp: Wright WPA 50-50 EAT KT88s
Analog: Marantz TT-15S1 MBS Glider SL| Wright WPP100C Amperex BB 6er5 and 7316 & WPM-100 SUT
Digital: Mac mini 2.3GHz dual-core i5 8g RAM 1.5 TB HDD Music Server Amarra (memory play) - USB - W4S DAC 2
Cables: Mits S3 IC and Spk cables| PS Audio PCs -
I would also suggest to anyone to try Toslink when connecting video or noisy equipment. I am currently running Toslink from my PC to my DAC and it seems to have cut some background noise.
Keep in mind that the HumX can only handle 6 amps.
