Ground Loop Hum AVR/Amp/HDMI

[TLS Guy]

Just an update on my issue. After trying everything I could manage (power conditioners, new cords, re-wiring/moving everything in the rack, trying to ground, fiber optic HDMI replacements, HumX and lifting grounds) the only thing that truly solved this issue without possibly violating electric codes (HumX and cheater plug for the amp) was buying the Jensen Iso-Mac CI-1RR and CI-2RR for between the AVR and amp. Although an espensive route, this killed the hum and everything is working great.

So that D Sonic amp has a poorly designed ground plane. It has a resistance between the power supply and signal ground. This sort of poor design is far too prevalent.

I have just been though a version of this with a computer power supply from Microcenter. It did not hum but it caused difficulty with booting, stuttering audio and noise when you moved the mouse. I could improve things by modifying the ground plane of the HTPC but to really solve it required booting the Microcenter power supply for a Corsair Gold at over twice the price. My son talked me into the $80 Microcenter PS, but I was suspicious and it turned out a POS.

 

[Chazmati]

Glad you found a fix. Fwiw, I developed a hum with my AV7705 and it would disappear when the receiver was off (and amps were still on). Turned out my antenna, feeding my monitor, had lost its ground, and the gym was coming back on the HDMI to the amp, I guess. When I re-grounded the antenna it was quiet again.

 

[Cory McComb]

I am having the same problem here. How and where do i hook up the jensen between the pre amp and avr properly ?
Thanks ahead of time i don't wanna mess anything up.

 

[TLS Guy]

I am having the same problem here. How and where do i hook up the jensen between the pre amp and avr properly ?
Thanks ahead of time i don't wanna mess anything up.

You need to explain exactly what your problem is and your set up. The correct answer is seldom that Jensen device. We don't know if you have a ground loop yet. If you do, most originate from cable and Ethernet connections.

 

[Cory McComb]

You need to explain exactly what your problem is and your set up. The correct answer is seldom that Jensen device. We don't know if you have a ground loop yet. If you do, most originate from cable and Ethernet connections.

I am getting a hum and static in audio when running pc video through hdmi. i have tried everything and bought the rolls he 18 similar to the jensen ci-2rr, pc gpu is evga 3080ti ftw 3 .
but not sure how to hook it up between amp and avr , im using a crown xls 1002 as a pre amp on a dennon 3700x avr.

 

[OldAndSlowDev]

I had a grounding humming issue with my setup, and it's because of "chance" that I finally figured out what was causing the humming. My amp, my appleTV and my PC were connected through ethernet to the router. AppleTV and my PC were also (of course) connected to my amp through hdmi. I first heard a humming in my subwoofer. After hours plugging everything on a single outlet with dedicated isolated grounding, I wasn't able to get rid of the humming, the only way was to disconnect the PC hdmi cable (with is REALLY strange as I got an optical extender, that shouldn't be part of any electric ground loop). I changed my internet provider so also changed my router. And then the humming noise was worse than ever. I then started to unplug everything, almost ready to cancel my new internet subscription to get back to the previous one when I realized something : when unpluging the amp ethernet cable, the humming was less obvious. Then I unplugged the AppleTV ethernet, no more humming. Then I plugged the hdmi coming from the PC : no humming in what was the worse configuration. So I realized that it's the ethernet hub that generates a lot of noise. Now my AppleTV and my Amp are using wifi, which against everything I would have thought is a better "audiophile" setup that using wires...

 

[TLS Guy]

I had a grounding humming issue with my setup, and it's because of "chance" that I finally figured out what was causing the humming. My amp, my appleTV and my PC were connected through ethernet to the router. AppleTV and my PC were also (of course) connected to my amp through hdmi. I first heard a humming in my subwoofer. After hours plugging everything on a single outlet with dedicated isolated grounding, I wasn't able to get rid of the humming, the only way was to disconnect the PC hdmi cable (with is REALLY strange as I got an optical extender, that shouldn't be part of any electric ground loop). I changed my internet provider so also changed my router. And then the humming noise was worse than ever. I then started to unplug everything, almost ready to cancel my new internet subscription to get back to the previous one when I realized something : when unpluging the amp ethernet cable, the humming was less obvious. Then I unplugged the AppleTV ethernet, no more humming. Then I plugged the hdmi coming from the PC : no humming in what was the worse configuration. So I realized that it's the ethernet hub that generates a lot of noise. Now my AppleTV and my Amp are using wifi, which against everything I would have thought is a better "audiophile" setup that using wires...

Cable/internet service is one of the commonest sources of ground loop hum. I would bet your installer who did your original installation did not do it to code.
Your service should enter the home as close to your panel as possible and be grounded at you panel with a robust grounding cable.

Obviously your service is not at true ground, and it should be. This needs correcting as it makes your house vulnerable to atmospheric severe weather episodes.

A wired ethernet connection is preferable to Wi-Fi. You should never do a firmware update vis Wi-Fi for instance.

When any installer turns up from a cable/internet provider, I watch their every move, and make sure they do nothing not to code. I am extremely strict with them.

I have zero hum from my cable system.

 

[OldAndSlowDev]

Cable/internet service is one of the commonest sources of ground loop hum. I would bet your installer who did your original installation did not do it to code.
Your service should enter the home as close to your panel as possible and be grounded at you panel with a robust grounding cable.

Obviously your service is not at true ground, and it should be. This needs correcting as it makes your house vulnerable to atmospheric severe weather episodes.

A wired ethernet connection is preferable to Wi-Fi. You should never do a firmware update vis Wi-Fi for instance.

When any installer turns up from a cable/internet provider, I watch their every move, and make sure they do nothing not to code. I am extremely strict with them.

I have zero hum from my cable system.

Oooh that could explain a lot. It's totally possible that the cable isn't grounded at all...

 

[TLS Guy]

Oooh that could explain a lot. It's totally possible that the cable isn't grounded at all...

If that is so, it a dangerous, serious code violation and needs correcting immediately. If there is hum though, it is more likely grounded improperly. The cause of ground loop hum is a resistance between grounds. I other words, ALL grounds have to be a equipotential, no exceptions.

 

[OldAndSlowDev]

If that is so, it a dangerous, serious code violation and needs correcting immediately. If there is hum though, it is more likely grounded improperly. The cause of ground loop hum is a resistance between grounds. I other words, ALL grounds have to be a equipotential, no exceptions.

My provider comes tomorrow morning to check that. Thank you very much to pointing toward that.

 

[OldAndSlowDev]

After check it's perfectly grounded. My issue really comes from having loops between devices through hdmi and ethernet. I'll stick with wifi.