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

wklie said:
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).
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These are, supposedly, 18Gbps. I suspect it was something in how they translate or decode EDID but can't be sure. With the Toshiba, it is so old that it conforms to a really early version of the HDMI standard and this cable possibly doesn't support. As for the ROKU 4K streamer, who knows. If you know anybody at FIBBR it would be nice to have them provide tech support either via Amazon or here but I do understand that's not anything you can do.

Also, a cable manufacturer that advertises that their cables are "firmware upgradeable" could possibly fix things if they would only talk to the end user like Pixel Magic does.
 
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.
 
Insufficient power is very possible with the FIBBR implementation. The fact that the Monoprice fiber optic cable works fine leads me to suspect that either there is enough power at both ends of the cable for conversion or the architecture of the cable, possibly a hybrid optical for signal and copper for power, mitigates the potential power issue. The Celerity Tech cables I have coming in today do have a USB umbilical at both ends just in case the ports, source or display side, don't supply any or sufficient power to operate properly. I'll report back about what I find with these different cables known to be a pure fiber implementation.
 
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
 
I have a Power Plant 20 in my system and tried every way I can think of to configure things to eliminate the hum and I do have an independent 10 AWG-fed subpanel that is used by the audio system. I suspect you are right regarding brands because it may be a design peculiarity with my HT processor, currently a Marantz AV8500, as there was no "audible" issue with my previous McIntosh MX-160.
 
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.
 
radioactive said:
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.
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"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???:rolleyes:

I am in N. VA., too. Ashburn.
 
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.

sleepysurf said:
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.
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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. :wave:

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???:rolleyes:

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

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Hopefully somebody else will benefit from my adventure.
 

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sleepysurf said:
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.

attachment.php


Hopefully somebody else will benefit from my adventure.
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Not tracking here, how did you run the main coax to the family room but still split the cable twice?




Sent from my iPhone using Tapatalk Pro
 
UltraFast69 said:
...how did you run the main coax to the family room but still split the cable twice?...
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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.
 
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.
 
brad225 said:
...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.
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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/f...-adds-up-to-bleak-financial-outlook-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.
 
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