audio ground loop

[PoorOwner]

Audio issue here, 2 circuits in the room.
When I plug one audio device 1 in circuit 1, and plug device 2 to circuit 2.

both devices are connected via an interconnect cable (RCA / HDMI etc)

There is a big ground loop hum. Text book example, right?

Can I custom wire device 2 so it is using neutral and hot from circuit 2, and ground from circuit 1?
In theory, the ground loop should be gone? While maintaining ground fault safety?

The two circuits are adjacent breakers in the same panel. The ground wires go to the same panel same ground bar.

I kept searching this issue and those crazy audio "file" people say they just don't use the ground wire. No way I am doing that.

 

[wyliesdiesels]

What are the devices?

 

[PoorOwner]

receiver and projector connected via HDMI.

I also want to plug in a subwoofer later on, same challenge.

 

[Jkcolo22]

Isn’t this what power conditioners are for?


Sent from my iPhone using Tapatalk

 

[slow]

Does your hdmi not support audio? I would ditch the rca if you can

 

[PoorOwner]

The HDMI cable does carrying a signal ground.
My solution right now is a long extension cord and plugging everything into the same circuit.

 

[Tmart86]

Something is broke in one or the other piece of equipment.

 

[SGKent]

When I plug one audio device 1 in circuit 1, and plug device 2 to circuit 2.

both devices are connected via an interconnect cable (RCA / HDMI etc)

PoorOwner - your explanation is hard to understand. It almost sounds like you have central Device A connected to Device 1 via HDMI, central Device A connected to Device 2 via HDMI, and Devices 1 & 2 connected to each other via RCA. Is this correct?

Please list the devices you are trying to interconnect, and which one(s) is/are creating the hum.

 

[nh_yota]

Just get a ground loop isolator and plug it in-line with the audio cables between the two devices.

 

[malibu101]

I don't know much about this stuff at all.
I have sometimes seen "ground lifters" used on audio mic cables at live events although I'm not really sure why.

I just thought these sounded like something along the lines of your problem. ?

Example- https://www.amazon.com/dp/B00FC4YPL4/?tag=atomicindus08-20

 

[PoorOwner]

PoorOwner - your explanation is hard to understand. It almost sounds like you have central Device A connected to Device 1 via HDMI, central Device A connected to Device 2 via HDMI, and Devices 1 & 2 connected to each other via RCA. Is this correct?

Please list the devices you are trying to interconnect, and which one(s) is/are creating the hum.

I have an amplifier on circuit 1 and a projector on circuit 2.

When I plug in the projector (into the wall) makes a loud hum in the speakers connected to the amplifier.

In terms of LOW voltage connections it goes
projector <-hdmi-> receiver <-rca-> amplifier.

receiver and amp plugged into circuit 1.

when I unplug the HDMI cable from the receiver or unplug the projector, the hum goes away. No TV cable is connected to the system.

 

[Mr. T]

Do the amp and projector both use a three prong plug?

 

[country83]

Some audio schematics I've seen for buildings specify "same phase same leg" for connected equipment. If you have them on adjacent breakers they would be on opposite legs. Try changing to the same leg and see if the issue goes away.

Sent from my XT1635-01 using Tapatalk

 

[PoorOwner]

Do the amp and projector both use a three prong plug?

yes. that's when i first noticed this issue. used to be a 2 prong amp no noise

 

[Jazzman442]

On certain audio devices that will happen. This will fix your problem:

https://www.homedepot.com/p/GE-Pola...ERCH=REC-_-pipsem-_-203684998-_-203744887-_-N

 

[PoorOwner]

I didn't want to lift the ground on the projector, but I am pretty sure the noise will go away.

So my original question is can I ground the projector using the same ground as the amp.
It's a bit of a hack, but it is safer than no ground.
If I swap the ground wire over, is there any scenario you can think of a ground fault would not trip a breaker ?

 

[PoorOwner]

On certain audio devices that will happen. This will fix your problem:

https://www.homedepot.com/p/GE-Pola...ERCH=REC-_-pipsem-_-203684998-_-203744887-_-N

I found one around the house. The system noise all gone with it.

 

[wyliesdiesels]

I didn't want to lift the ground on the projector, but I am pretty sure the noise will go away.

So my original question is can I ground the projector using the same ground as the amp.
It's a bit of a hack, but it is safer than no ground.
If I swap the ground wire over, is there any scenario you can think of a ground fault would not trip a breaker ?

If youre asking if its NEC compliant then the answer is no.

 

[jeffmoss26]

you could try a 2 to 3 prong adapter for your power and see what happens.

 

[ASHMAN_AZ]

Some audio schematics I've seen for buildings specify "same phase same leg" for connected equipment. If you have them on adjacent breakers they would be on opposite legs. Try changing to the same leg and see if the issue goes away.

Sent from my XT1635-01 using Tapatalk

This is good advice.

I am having a similar issue with my outside cheap TCL porch TV connected to the inside main stereo. The RCA ground loop isolators helped remove most of the hum, a power conditioner at the AMP rack did not help. I have three different breakers between my main TV, AMPs and out side TV all ground looped by RCA cables.

 

[wyliesdiesels]

This is good advice.

I am having a similar issue with my outside cheap TCL porch TV connected to the inside main stereo. The RCA ground loop isolators helped remove most of the hum, a power conditioner at the AMP rack did not help. I have three different breakers between my main TV, AMPs and out side TV all ground looped by RCA cables.

different breakers are not the issue. Just make sure theyre on the same hot leg in the panel.

 

[SGKent]

yes. that's when i first noticed this issue. used to be a 2 prong amp no noise

Were you the one who rewired the two prong plugs to 3 prong, or did you move from a house that had 2 prong receptacles with no ground?

 

[PoorOwner]

Were you the one who rewired the two prong to 3 prong?

No.. I changed the amplifier to a different brand and it is a bit different. lesson learned. keep everything either 2 or 3 prong and don't mix them.