Thread: Ground loop hum eliminated.............. the expensive way!

Congratulations !

Hum like that can be annoying. So happy you found a way to eliminate it.

Hmmm (re hummm), I've had that exact problem with HDMI "contaminating" my 2 channel system (when connected to my Oppo player). What brand fiberoptic HDMI cable have y'all used? Does it require some kind of optical to electric converter to work with older HDTV's?

I ordered this FURUI brand fiber HDMI cable from Amazon, which also offered shorter lengths, and less expensive than the FIBBR series... https://www.amazon.com/dp/B07CGKDQDD.

It arrived today, but, unfortunately, did NOT eliminate the ground loop hum in my setup. Fortunately, FURUI allowed me to return it for full refund.

I wonder if the FIBBR design is different, and still might work?

Yes, I've confirmed it's the HDMI cable running from my Oppo UDP 205 (likewise with older BDP 95) to my Denon receiver into Sony HDTV. Everything is plugged into the same circuit. I've struggled with this for years... even trying an Ebtech Hum X on the Oppo, C-J Preamp, and Denon respectfully, without success. I've dealt with it by connecting the HDMI cable only when watching a DVD.

I'll contact FIBBR to see if they likewise offer refund if it doesn't work.

Does lifting the ground on the Oppo do anything?

Are you sure it’s a ground loop and not just noise in your system? Does it adjust with volume?

Unplug everything, and I mean everything then start with the amp to the speaker and see what happens. Then start plugging in everything until you hear the hum.

Ensure all power cables are not running parallel alongside interconnects and speaker cable.






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Also is there a cable or satellite box in this setup?

Originally Posted by Jack

Also is there a cable or satellite box in this setup?

Good point Jack


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Originally Posted by sleepysurf

What brand fiberoptic HDMI cable have y'all used? Does it require some kind of optical to electric converter to work with older HDTV's?

In my geographic area, FIBBR and Moshou are more popular with videophiles. I use a cheaper brand SGO.

You use it just like any other HDMI cable regardless of what kind of HDMI device you have.

However, they draw power from the HDMI devices they connect to for the optical conversion electronics, so there may be incompatibility with specific devices. It's best to make sure you can return the cable if it does not work for you.

Very often antenna feed also causes ground loop issues. Some people got rid of it by a ground isolator for the antenna.

Originally Posted by Jack

Does lifting the ground on the Oppo do anything?

No. Lifting the ground does not help. Antenna coax to cable box is, likewise, not the source. The hum is not related to preamp volume, so not tube noise. It's clearly due to the HDMI connection to my old Denon receiver, HDTV, and Frontier cable box. Interestingly, unplugging all three of those simultaneously eliminates the hum, but unplugging each of them individually does not, so I can't isolate it to any specific component. Those are all powered by a Monster HTS 3500 conditioner (plugged into same 20A outlet as the rest of my system), so it's possible that device is the source of the problem. I'll try the FIBBR cable next, before pulling the Monster conditioner out of the system.

Of note, I emailed FIBBR asking if they'd confirm their design can eliminate a ground loop, but never heard back. Guess I'll just buy it from Amazon, and return it if it doesn't work.

I opened the cable housing box (you may have this inside or outside) where the cable comes in from noticed there is a grounding wire along side the incoming cable and noticed it was not tight, I mean it was like a little better then finger tight. After I tightened this down things improved.




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If the Frontier cable box is integrated into a joint two channel/HT setup then having any of the three HDMI cables connected will cause the noise. So disconnecting the cable box from the incoming line alone doesn't stop the hum? Have you tried to take the Frontier box in and swap it for a new one? I doubt it is the HTS-3500 if the common denominator for stopping the hum is removing the HDMI cables. And like Ultrafast said check the cable companies ground wire at the junction box.

Originally Posted by BlueSky

I had problems with FIBBRs cables. Two of my sources worked fine. Two did not "like" the cables.

As I said in post #14.

Also note that there are different grades of fiber HDMI cable. Only 18Gbps version should be used - but with some brands it costs much more than 10.2Gbps versions (not good).

My hypothesis / speculation is that a source may simply not have enough power to drive the fiber conversion inside the cable. This is why another less convenient variation exists that takes power from an additional USB connection. However, even with external USB power it does not imply it has to be compatible with everything.

Interesting that you call this the expensive way. Because you're almost right - there are more expensive ways - like highly expensive power regenerators.

The cheaper, and easier way to fix is to have a direct line run from your electrical panel to your gear. In every situation I've experienced such humming, that has resolved the hum. In addition, it improved the picture quality and removed noise oad other visual issues.

One other thing was the brand I was using. Some are worse than other - both the AV, Amplifier(s) and Processors, can introduce noise.

Bryan

Strange you're not having the issue on the McIntosh unit and are on the Marantz because they're both Marantz units. Albeit the McIntosh has had some "special treatment" that adds $$ to it.

You can also try grounding the chassis of the units together -- sometimes that works - especially on source devices. Be careful of certain amps though if you do this because of how they're wired. Mostly your tube and direct coupled amps do strange things with their chassis.

Hi, I was just reading over your post and thought I should comment. I had that exact same Monster HTS 3500. I had it in my rack with my AV gear in our living room. Boy was I proud of it -- it was my first foray into anything power protection that wasn't a strip. I bought it in like 2005-2007 or so, maybe a bit later. I ended up with a hum suddenly and couldn't figure out what it was. It turned out to be several things, I had just not noticed as I don't watch tv in that room (the family does, but I seldom had time those days). Needless to say, it was the Monster unit itself causing all the humming. I was quite shocked. It's got specific inputs on the back, some for digital equipment, other's for amps, etc. I thought that was the problem and when I connected everything as it should be, the humming went down some, but not completely. I thought I had figured out the other half of the problem as a previous poster has said about the grounding of the RG6 coming inside of your house not being properly grounded. Once I did that, the noise almost went away. Eventually, I just bought a power strip with surge protection that was long enough to go in the Salamander unit I had it all in and the noise went away. I thought it was a fluke so I tried that HTS 3500 MKII in another room and the humming returned.

I ended up returning it to the Myer Emco I purchased it from (now out of business). It was just outside of a year, but I had spent a lot of money there so they swapped it out for another unit, which did not have that hum.

Moral to the story - power filters go bad. Don't forget to rule them out along with your gear.

Originally Posted by sleepysurf

No. Lifting the ground does not help. Antenna coax to cable box is, likewise, not the source. The hum is not related to preamp volume, so not tube noise. It's clearly due to the HDMI connection to my old Denon receiver, HDTV, and Frontier cable box. Interestingly, unplugging all three of those simultaneously eliminates the hum, but unplugging each of them individually does not, so I can't isolate it to any specific component. Those are all powered by a Monster HTS 3500 conditioner (plugged into same 20A outlet as the rest of my system), so it's possible that device is the source of the problem. I'll try the FIBBR cable next, before pulling the Monster conditioner out of the system.

Of note, I emailed FIBBR asking if they'd confirm their design can eliminate a ground loop, but never heard back. Guess I'll just buy it from Amazon, and return it if it doesn't work.

Nice to meet a fellow N. Va'er. I'm in Leesburg so we're just down 7 (or the wallet sucking toll road) from each other.

2 Feet? Why so close? Sorry to get off topic, you just have me curious.

Not sure you've played with this, but just in case: depending on your source, you may have control over the output voltage if you're using XLR/Balanced connectors. I know my Rossini has the ability to switch the output level from 2V to 6V. If your preamp/amp can handle the 6V, you can use that option and turn down the gain on your amps because your signal is much higher. You can also try the converse and see how things turn out. I've found this to be useful when trying to get the noise floor down or get the best sound out of a unit. I also find that it makes a huge difference in sound quality depending on the source. Hopefully your preamp has the ability to set levels on inputs separately so you can have some unity between inputs when you select them.

ps...you should update your signature with your setup. When you post questions, it will help when others can see what you're using as they may know of issues or configurations specific to your gear/environment -- of course as long as you're comfortable with it. Trust me, none of us are "showboating" here. It's just kind of a way to say what we have so we don't have to sniff butts LOL (sorry, if you're not a dog person - well, just sorry).

QUOTE=BlueSky;272591]"Special" indeed. I've got several meter long cables with alligator clips on both ends that I try from time but to no avail. I wish the front three amps had gain controls to I could lower the noise floor a little more. I suppose I could get some passive XLR attenuators and try that route if my obsession really kicks in. I may be just too sensitive because who listens to they system within a foot or two of the front speakers???

I am in N. VA., too. Ashburn.[/QUOTE]

Welcome to the forum, thank you for joining.

FINALLY solved the ground loop hum! Neither of the fiber HDMI cables helped. Turns out, the culprit (as always suspected) was my Frontier cable coax. However, inserting a Jensen coax ground loop isolator, while eliminating the ground loop, blocked all the analog TV channels (too much signal loss). I had TWO Frontier Techs spend 3 hrs troubleshooting last week, to no avail. They said my signal was more than adequate, but agreed to replace my ONT, and re-ground it. They also replaced the 8-port splitter at my structured wiring hub. Still had the loud hum. They gave up, and suggested I just switch to their Master/Slave wireless set-top box system (for much more $$). I declined, and continued trouble-shooting on my own.

I finally figured out the 8-port splitter was the problem, as each successive split decreases the signal by an additional 50%. As a test, I eliminated the splitter altogether, running the main coax directly to my Family/Listening Room, and this approach eliminated the ground loop, while preserving adequate TV signal. I next added a 2-port splitter, and the signal was still adequate. I then daisy-chained a 4-port splitter off the first, for the remaining TV's in the house, and also terminated an unused port with a 75 Ohm cap. The signal was still adequate for the other TV's (since they didn't need the isolator). I can't believe the Frontier Tech guys didn't think of that!

Anyways, I'm now a happy camper, and able to fully enjoy my integrated 2-channel and Home Theater setup with a dead silent background.

Here's a pic of the daisy-chained splitters.



Hopefully somebody else will benefit from my adventure.

Originally Posted by sleepysurf

FINALLY solved the ground loop hum! Neither of the fiber HDMI cables helped. Turns out, the culprit (as always suspected) was my Frontier cable coax. However, inserting a Jensen coax ground loop isolator, while eliminating the ground loop, blocked all the analog TV channels (too much signal loss). I had TWO Frontier Techs spend 3 hrs troubleshooting last week, to no avail. They said my signal was more than adequate, but agreed to replace my ONT, and re-ground it. They also replaced the 8-port splitter at my structured wiring hub. Still had the loud hum. They gave up, and suggested I just switch to their Master/Slave wireless set-top box system (for much more $$). I declined, and continued trouble-shooting on my own.

I finally figured out the 8-port splitter was the problem, as each successive split decreases the signal by an additional 50%. As a test, I eliminated the splitter altogether, running the main coax directly to my Family/Listening Room, and this approach eliminated the ground loop, while preserving adequate TV signal. I next added a 2-port splitter, and the signal was still adequate. I then daisy-chained a 4-port splitter off the first, for the remaining TV's in the house, and also terminated an unused port with a 75 Ohm cap. The signal was still adequate for the other TV's (since they didn't need the isolator). I can't believe the Frontier Tech guys didn't think of that!

Anyways, I'm now a happy camper, and able to fully enjoy my integrated 2-channel and Home Theater setup with a dead silent background.

Here's a pic of the daisy-chained splitters.



Hopefully somebody else will benefit from my adventure.

Not tracking here, how did you run the main coax to the family room but still split the cable twice?




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Originally Posted by UltraFast69

...how did you run the main coax to the family room but still split the cable twice?...

Main coax into 2-port splitter... 1st split (50% signal loss) goes direct to Family/Listening Room (with Jensen isolator at that end), and 2nd split (also 50% signal loss) feeds into a 4-port splitter. All those subsequent splits lose another 50% of signal (net 75% signal loss), but still sufficient for all remaining TV's.

Here's an updated pic which better explains the configuration.

Glad to hear you finally got it worked out. I wish they would allow fiber into the house. I have asked a number of people connected and they seem to have no idea if you could or why you would want to. Maybe they send the less savvy techs to areas outside Tampa proper. :-)

Frontier is virtually useless. I would pay Verizon 50% more than their normal billing if they would have stayed. Our ONT was replaced 8 weeks ago and has gone bad again. We will have a tech there in 10 days to work on it. None of the techs that have come here have had anything good to say about Frontier.

Originally Posted by brad225

...Our ONT was replaced 8 weeks ago and has gone bad again. We will have a tech there in 10 days to work on it. None of the techs that have come here have had anything good to say about Frontier.

Interestingly, the Techs that came to my house also complained about Frontier (vs. Verizon, for whom they previously worked). They both said their signal testing meters were broken, but Frontier hadn't replaced them (they used the service mode of my DVR to measure signal strength). According to this recent Tampa Bay Times article, Frontier (nationwide) is on the verge of bankruptcy... https://www.tampabay.com/business/fo...look-20190815/

They've created a vicious cycle of steeply raising rates, leading to even more "cable-cutters", and further spiraling revenues. I wonder what the future holds, both locally, and nationwide.