Ground loop hum?

[IceDoppio]

I had a 7.1 setup with a Marantz 5011 AVR. All was fine. I upgraded the projector to an Epson.

Still no issue.

I recently added Atmos height speakers and upgraded to Marantz 7013 AVR, so I can run 9.2 (Atmos 5.1.4).

That somehow introduced a terribly annoying hum that begins as soon as the projector is plugged in and the receiver is plugged in and turned on.

* The hum is clearly linked to the HDMI cable connection between the projector and the AVR. Plug in the HDMI cable, there is a hum. Disconnect it, there is no hum. But it's not the HDMI cable itself. I've tried different cables and it doesn't help!

* Nothing about the electrical setup has changed. All the components are plugged into a single power strip. I have taken an extension cord and tried plugging the power strip with all these devices into other outlets on other circuits. Each outlet I try results in a hum.

* If I fall back to the Marantz 5011 from the new Marantz 7013, the hum goes away.

* If I keep the Marantz 7013 in the mix, but use a flat panel as the output instead of the Epson projector with the same HDMI cable, the hum goes away.

* I am not using a cheater plug to "fix" the problem, but I did test it. I can confirm that if I take the projector and plug it into a cheater plug before plugging into the power strip, the hum goes away.

Of course . . . .

1. Marantz vendor says the problem is the projector--even tho the problem goes away if I plug into a flat panel instead of the projector.

2. Epson vendor says the problem is the receiver--even tho the receiver does not have a grounded plug and the hum goes away when I use my old Marantz 5011 instead of the new Marantz 7013.

Do I need to sort this out? Or is there a safe way to filter the connections to eliminate the hum?

 

[highfigh]

I had a 7.1 setup with a Marantz 5011 AVR. All was fine. I upgraded the projector to an Epson.

Still no issue.

I recently added Atmos height speakers and upgraded to Marantz 7013 AVR, so I can run 9.2 (Atmos 5.1.4).

That somehow introduced a terribly annoying hum that begins as soon as the projector is plugged in and the receiver is plugged in and turned on.

* The hum is clearly linked to the HDMI cable connection between the projector and the AVR. Plug in the HDMI cable, there is a hum. Disconnect it, there is no hum. But it's not the HDMI cable itself. I've tried different cables and it doesn't help!

* Nothing about the electrical setup has changed. All the components are plugged into a single power strip. I have taken an extension cord and tried plugging the power strip with all these devices into other outlets on other circuits. Each outlet I try results in a hum.

* If I fall back to the Marantz 5011 from the new Marantz 7013, the hum goes away.

* If I keep the Marantz 7013 in the mix, but use a flat panel as the output instead of the Epson projector with the same HDMI cable, the hum goes away.

* I am not using a cheater plug to "fix" the problem, but I did test it. I can confirm that if I take the projector and plug it into a cheater plug before plugging into the power strip, the hum goes away.

Of course . . . .

1. Marantz vendor says the problem is the projector--even tho the problem goes away if I plug into a flat panel instead of the projector.

2. Epson vendor says the problem is the receiver--even tho the receiver does not have a grounded plug and the hum goes away when I use my old Marantz 5011 instead of the new Marantz 7013.

Do I need to sort this out? Or is there a safe way to filter the connections to eliminate the hum?

Is there any chance that you ran a screw through the HDMI cable when you mounted the speakers?

 

[lovinthehd]

How about putting a ground loop isolator full time on the projector, that would possibly "fix" it. Or sort out the ground loop issue overall....is there cable tv or similar connected somewhere?

 

[IceDoppio]

Is there any chance that you ran a screw through the HDMI cable when you mounted the speakers?

No. The HDMI cable is not defective. And I have tried swapping in other HDMI cables. The only thing that works is:
1. Cheater plug—obviously not a fix
2. Plugging in my old Marantz AVS
3. Not using a projector at all and using a flat screen TV instead…not a solution that helps me much tho!

It does not help to:
1. Use a different projector
2. Use a different HDMI cable
3. Use a different power strip
4. Plug power strip into a different outlet—even one on a different circuit

 

[IceDoppio]

How about putting a ground loop isolator full time on the projector, that would possibly "fix" it. Or sort out the ground loop issue overall....is there cable tv or similar connected somewhere?

Is it safe to plug in an isolator? Or is that like the cheater plug—i.e., not a safe fix?

There is a cable tied to the TiVo that is an input on the receiver. BUT even with all the input devices disconnected—and the cable unplugged from the TiVO, I get the humming/buzzing sound.

The sound continues even with my old projector. So, it’s not specific to the new projector.
The sound goes away with my old reeciever.

So, signs point to the new AVR…

 

[highfigh]

No. The HDMI cable is not defective. And I have tried swapping in other HDMI cables. The only thing that works is:
1. Cheater plug—obviously not a fix
2. Plugging in my old Marantz AVS
3. Not using a projector at all and using a flat screen TV instead…not a solution that helps me much tho!

It does not help to:
1. Use a different projector
2. Use a different HDMI cable
3. Use a different power strip
4. Plug power strip into a different outlet—even one on a different circuit

You connected a different HDMI cable between the AVR and projector?

Was the projector's outlet installed recently? If so, maybe the electrician could assign it to the other phase of the electrical service. Have you checked the outlet for proper Hot/Neutral assignments?

If you have a piece of wire that's long enough (type isn't important), connect it between the AVR and projector- the AVR has a ground post below the ethernet port and the projector may, but you'll need to find a grounded screw if it doesn't. If the projector has a grounded power cord, measure resistance between the grounding pin in the IEC power inlet and a screw on the projector- once you find one, you can fasten the wire at the receiver and touch the end to the projector- if the hum stops, it means the wiring for the AVR and projector have resistance on the ground and/or neutral.