How to ground an AV receiver

[highfigh]

It would be sooooo easy for amplifier manufacturers to add a grounding screw, but that adds (pennies) to their cost, so.......

You could have used speaker wire.

 

[OriginalCin]

I figured that speaker wire might work, but I wanted to eliminate any variables created by my own lack of experience and went for a purpose-built grounding wire. ‍

Wouldn’t it be a good idea for most all components to have a grounding post?

 

[highfigh]

I figured that speaker wire might work, but I wanted to eliminate any variables created by my own lack of experience and went for a purpose-built grounding wire. ‍

Wouldn’t it be a good idea for most all components to have a grounding post?

Not necessarily- there's a scheme for grounding/bonding that is generally adhered to and that typically involves having one central device using a grounded power cord, then the others connected to it use an ungrounded cord. The shield of the signal cables (the shield isn't necessarily for the signal negative) is connected at the grounded device, allowing the shield to act as an antenna and send the interference to ground but ideally, the shield should be separate from the signal carrying conductors, as it is in balanced low impedance connections for commercial/industrial/pro AV gear. This last point is a large part of the reason people should use consumer OR pro gear, but not a mixed bag- if you read the threads about system noise, you'll see that almost all of them deal with using pro amplifiers with consumer AVRs.

This is a good paper to read- their site has a lot of useful information-

https://www.ranecommercial.com/legacy/note151.html

 

[Bsbllfit7]

Get a grounding wire and connect the Denon grounding post to any chassis screw on the amp. Got rid of my speaker buzz. I picked up a basic grounding wire from Amazon.
Phonograph Turntable Ground Wire... https://www.amazon.com/dp/B07Z9WB7W6?ref=ppx_pop_mob_ap_share

The only problem with my situation is neither device had a ground plug. Wouldn't I need to ground the receiver to the ground from the receptacle some how? Or is it enough to connect the amp to the AVR via a "ground wire" even though neither unit is grounded through their power wire?

 

[OriginalCin]

Not necessarily- there's a scheme for grounding/bonding that is generally adhered to and that typically involves having one central device using a grounded power cord, then the others connected to it use an ungrounded cord. The shield of the signal cables (the shield isn't necessarily for the signal negative) is connected at the grounded device, allowing the shield to act as an antenna and send the interference to ground but ideally, the shield should be separate from the signal carrying conductors, as it is in balanced low impedance connections for commercial/industrial/pro AV gear. This last point is a large part of the reason people should use consumer OR pro gear, but not a mixed bag- if you read the threads about system noise, you'll see that almost all of them deal with using pro amplifiers with consumer AVRs.

This is a good paper to read- their site has a lot of useful information-

https://www.ranecommercial.com/legacy/note151.html

Thanks for the info. Happy New Year!

 

[highfigh]

The only problem with my situation is neither device had a ground plug. Wouldn't I need to ground the receiver to the ground from the receptacle some how? Or is it enough to connect the amp to the AVR via a "ground wire" even though neither unit is grounded through their power wire?

Does the AVR's power cord have three pins? If not, look at the inlet on the back- if that has three pins and the cord has only two, get a different cord that has three.

 

[Hilox]

Not willing to create a new post as this thread has a lot of info which applies to me also but i can´t really get what should be grounded first, please bare with me.

My setup at home is an Marantz SR7500 - DBX-PA2 signal processor - Opera 415MK2 as main active speakers + 2 B1500D subs; the other surround speakers + center are connected directly to the receiver. My problem is similar to this my getting some static noise in the mains, kind like a cassette player hiss when no music is played and sometimes even a buzzing noise. I tried to set all proper levels but ended up with setting the levels very low to get rid of the hissing noise, so reading this thread made me think that actually none of the equipment is grounded atm. and reading through this thread i´m not quite sure on what equipment should be grounded "first" as the receiver does not have any grounding. I use, of course non balanced pre-outs for front and sub to the DBX processor and from there on all are balanced and the reason for the equip not being grounded is that i use the Aqara ZigBee plugs with an EU converter (live in Sweden) to be able to power on all the hi-fi in an special order through my automation system.

So do i got this right if my "grounding scheme" looks like this; connect the operas to a grounded outlet (as only those have the ground screw on the chassis plate) and from there start to ground the DBX - av receiver and the subs? Or am i totally out in the clouds?

Thanks

 

[TLS Guy]

Not willing to create a new post as this thread has a lot of info which applies to me also but i can´t really get what should be grounded first, please bare with me.

My setup at home is an Marantz SR7500 - DBX-PA2 signal processor - Opera 415MK2 as main active speakers + 2 B1500D subs; the other surround speakers + center are connected directly to the receiver. My problem is similar to this my getting some static noise in the mains, kind like a cassette player hiss when no music is played and sometimes even a buzzing noise. I tried to set all proper levels but ended up with setting the levels very low to get rid of the hissing noise, so reading this thread made me think that actually none of the equipment is grounded atm. and reading through this thread i´m not quite sure on what equipment should be grounded "first" as the receiver does not have any grounding. I use, of course non balanced pre-outs for front and sub to the DBX processor and from there on all are balanced and the reason for the equip not being grounded is that i use the Aqara ZigBee plugs with an EU converter (live in Sweden) to be able to power on all the hi-fi in an special order through my automation system.

So do i got this right if my "grounding scheme" looks like this; connect the operas to a grounded outlet (as only those have the ground screw on the chassis plate) and from there start to ground the DBX - av receiver and the subs? Or am i totally out in the clouds?

Thanks

Your hissing sound is from poor signal to noise ratio in one or more items of equipment in the chain. All except the Marantz are low end pro units.

Those Opera speakers, look particularly nasty. Behringer are known for some pretty rough gear. The F3 point of those subs is 35 Hz so not really subs at all, but mid bass units. You hiss is not a ground loop, but cheap amps.

 

[Hilox]

Ok cool, well i have had the gear for at least 10 years now apart from the DBX and bought them basically as new, only used in home environment. I can´t recall though that the hissing/buzzing was so evident at my old place but there, for a time i´ve also used a couple of Cantons rc-l and a perless xls12-radiator sub which did a pretty good job for the 16m2 livingroom. Later at my new place with the room being 60m2 and a ceiling height between 3,60m to 4,80m in a stone villa, that setup doesn't even come near of what the Operas and the 1500d subs... sorry, midbases performs. So based on the review (kind a like asking a Porsche dealer review my 00´s Volvon, but yeah, my blame) i´d might look for some new stuff then but in my grounding quest, would my previous question be a way forward? Or should i just leave it ungrounded.

Thanks

 

[TLS Guy]

Ok cool, well i have had the gear for at least 10 years now apart from the DBX and bought them basically as new, only used in home environment. I can´t recall though that the hissing/buzzing was so evident at my old place but there, for a time i´ve also used a couple of Cantons rc-l and a perless xls12-radiator sub which did a pretty good job for the 16m2 livingroom. Later at my new place with the room being 60m2 and a ceiling height between 3,60m to 4,80m in a stone villa, that setup doesn't even come near of what the Operas and the 1500d subs... sorry, midbases performs. So based on the review (kind a like asking a Porsche dealer review my 00´s Volvon, but yeah, my blame) i´d might look for some new stuff then but in my grounding quest, would my previous question be a way forward? Or should i just leave it ungrounded.

Thanks

You will not cure the hiss with grounding, but the hum you might. Since the hm is intermittent that is doubtful.

 

[hutt132]

Best practice is to ground the preamp, which in your case is the receiver and keep the power amp bonded to the receiver and lift the ground to the power amp entirely. I always ground the preamp and make sure the power amp stays connected. The power amp is then grounded though the shield.

I have an interesting problem with ground and surges and hope you could shed some light.
I don't have any hum, but I keep having lightning surges fry the HDMI ports on my receiver.
I have two whole home surge protectors and no other wires or metal pipes coming into my home, the internet is fiber.

My setup is a Denon x4700h which only has a 2 prong power cable, no ground connection.
I have a computer that has 3 prong power cable on the same circuit, so it is grounded.
The Denon and computer are connected with an HDMI cable.
The HDMI cable is acting as a ground from the Denon to the computer through the HDMI cable's shielding.
Both the Denon and computer are plugged into a Zero Surge 2R20W surge protector.

Surges keep frying the HDMI port on the Denon receiver. I'm assuming the surge is low voltage enough to bypass the whole home surge protectors, comes through the mains into the Denon, and seeks ground through the HDMI cable and through the computer's ground.

Would adding a ground connection from the Denon to the outlet ground help mitigate this issue?

 

[TLS Guy]

I have an interesting problem with ground and surges and hope you could shed some light.
I don't have any hum, but I keep having lightning surges fry the HDMI ports on my receiver.
I have two whole home surge protectors and no other wires or metal pipes coming into my home, the internet is fiber.

My setup is a Denon x4700h which only has a 2 prong power cable, no ground connection.
I have a computer that has 3 prong power cable on the same circuit, so it is grounded.
The Denon and computer are connected with an HDMI cable.
The HDMI cable is acting as a ground from the Denon to the computer through the HDMI cable's shielding.
Both the Denon and computer are plugged into a Zero Surge 2R20W surge protector.

Surges keep frying the HDMI port on the Denon receiver. I'm assuming the surge is low voltage enough to bypass the whole home surge protectors, comes through the mains into the Denon, and seeks ground through the HDMI cable and through the computer's ground.

Would adding a ground connection from the Denon to the outlet ground help mitigate this issue?

My first question is how do you know it is caused by lightning?

One good ground should be enough. Those receivers are double insulated.

So a surge protector at service entry and one at your panel should suffice.

The next issue is, do you have enough ventilation to your unit? Heat kills, especially HDMI boards.

The next issue is, are you powering anything from your HDMI ports without using a voltage inserter? For instance are you using an active HDMI cable?

Are all your HDMI failures associated with electrical storms when lights are flickering?

If the answer to all those questions is negative, then you could possibly consider a UPS, which goes to battery as soon as AC power is out of spec. However receivers have power amps, and it is not usually considered good practice to power a receiver via an Uninterruptible Power Supply.

That is one of many reasons I don't use receivers. I use AVPs and power amps. Everything except the power amps are connected via a UPS.

Lastly I do note that model receiver was known for HDMI problems, but I assume that since you have replaced the HDMI board due to these failures, you have the updated boards, but you might want to check that.

 

[Speedskater]

Everything connected together via HDMI cables, should be plugged into the ZeroSurge.

* * * * * * * * * * * * *
For other readers.
If your A/V equipment is protected by more than one 'point of use' surge protector.
They should all be the same brand, model and vintage.
Different brands can limit at different voltages.

 

[hutt132]

Everything connected together via HDMI cables, should be plugged into the ZeroSurge.

* * * * * * * * * * * * *
For other readers.
If your A/V equipment is protected by more than one 'point of use' surge protector.
They should all be the same brand, model and vintage.
Different brands can limit at different voltages.

This is true. Both the Denon and computer are plugged into the ZeroSurge.

My first question is how do you know it is caused by lightning?

One good ground should be enough. Those receivers are double insulated.

So a surge protector at service entry and one at your panel should suffice.

The next issue is, do you have enough ventilation to your unit? Heat kills, especially HDMI boards.

The next issue is, are you powering anything from your HDMI ports without using a voltage inserter? For instance are you using an active HDMI cable?

Are all your HDMI failures associated with electrical storms when lights are flickering?

If the answer to all those questions is negative, then you could possibly consider a UPS, which goes to battery as soon as AC power is out of spec. However receivers have power amps, and it is not usually considered good practice to power a receiver via an Uninterruptible Power Supply.

That is one of many reasons I don't use receivers. I use AVPs and power amps. Everything except the power amps are connected via a UPS.

Lastly I do note that model receiver was known for HDMI problems, but I assume that since you have replaced the HDMI board due to these failures, you have the updated boards, but you might want to check that.

The unit could use some more ventilation, I'll look into this aspect.
I am not using active HDMI cables.
All of the HDMI failures are associated with electrical storms. I'm in Florida.
This time, only the one HDMI port that the cable was plugged into stopped working. The other HDMI ports are working, so this is why I think it was lightning again.
The last time I had the HDMI board replaced was June 2021. It's out of warranty now so I don't know how I'm going to get it fixed this time.

I do actually have the Denon and computer on a CyberPower UPS plugged into the Zero Surge protector. I did this after the first time the HDMI board fried.

I was thinking of grounding out the Denon chassis to the outlet, and getting a pure fiber HDMI cable that has a voltage inserter on each end. That way there is no electrical connection between the computer and Denon. Like this one https://shop.fibercommand.com/products/purefiber-ultravision-hdmi-2-1-48gbps-4k120hz-8k60hz-hdr-bundle-cable.

 

[TLS Guy]

This is true. Both the Denon and computer are plugged into the ZeroSurge.


The unit could use some more ventilation, I'll look into this aspect.
I am not using active HDMI cables.
All of the HDMI failures are associated with electrical storms. I'm in Florida.
This time, only the one HDMI port that the cable was plugged into stopped working. The other HDMI ports are working, so this is why I think it was lightning again.
The last time I had the HDMI board replaced was June 2021. It's out of warranty now so I don't know how I'm going to get it fixed this time.

I do actually have the Denon and computer on a CyberPower UPS plugged into the Zero Surge protector. I did this after the first time the HDMI board fried.

I was thinking of grounding out the Denon chassis to the outlet, and getting a pure fiber HDMI cable that has a voltage inserter on each end. That way there is no electrical connection between the computer and Denon. Like this one https://shop.fibercommand.com/products/purefiber-ultravision-hdmi-2-1-48gbps-4k120hz-8k60hz-hdr-bundle-cable.

Do not use surge protectors if you have whole house surge protection.

I would absolutely not connect your AVR to the UPS. Power amps are highly inductive loads, and as the UPS switches then high voltages can be created.

If you replace your receiver, then seriously consider an AVP and power amps given your situation.

You certainly should attend to your ventilation issues.

Minnesota is also bad for electrical storms and we have had some bad ones, including a direct hit, and my plans held and we only lost a 'slave' Comcast box in the living room even though it was connected to a UPS.

 

[hutt132]

Do not use surge protectors if you have whole house surge protection.

I would absolutely not connect your AVR to the UPS. Power amps are highly inductive loads, and as the UPS switches then high voltages can be created.

If you replace your receiver, then seriously consider an AVP and power amps given your situation.

You certainly should attend to your ventilation issues.

Minnesota is also bad for electrical storms and we have had some bad ones, including a direct hit, and my plans held and we only lost a 'slave' Comcast box in the living room even though it was connected to a UPS.

It was my understand that "regular" surge protectors are type 3 and "SPD Type 3 is designed specifically aimed at protecting specific terminal equipment, they should be installed close to sensitive loads as a supplement to Type 2 SPDs." And whole home surge protectors are Type 2 SPD.

However, if you're suggesting the type 3 SPD could be more harmful in this scenario I will remove it since I have a type 2 SPD (whole home).

I drove 2 20ft solid copper ground rods (coupled together 18' apart) with the first rod wired within 6' to the utility panel using solid copper #4 wire.
Have a whole home Siemens FS140 surge protector on the utility panel.
Have an additional whole home Siemens Boltshield surge protector on the inside breaker panel. (Siemens recommends having multiple Type 2 SPD for more protection.)

I'll take the AVR off the UPS as you recommended.
I could leave the computer on the CyberPower UPS, however the UPS also has an integrated 1330 Joule MOV surge protector in it. If you think this integrated surge protector is an issue since I have a whole home protector, I can remove the UPS entirely. But then the computer would be susceptible to brown outs.

Really appreciate your help so far. It's a lot to visualize on how to fix my surge issues.

 

[TLS Guy]

It was my understand that "regular" surge protectors are type 3 and "SPD Type 3 is designed specifically aimed at protecting specific terminal equipment, they should be installed close to sensitive loads as a supplement to Type 2 SPDs." And whole home surge protectors are Type 2 SPD.

However, if you're suggesting the type 3 SPD could be more harmful in this scenario I will remove it since I have a type 2 SPD (whole home).

I drove 2 20ft solid copper ground rods (coupled together 18' apart) with the first rod wired within 6' to the utility panel using solid copper #4 wire.
Have a whole home Siemens FS140 surge protector on the utility panel.
Have an additional whole home Siemens Boltshield surge protector on the inside breaker panel. (Siemens recommends having multiple Type 2 SPD for more protection.)

I'll take the AVR off the UPS as you recommended.
I could leave the computer on the CyberPower UPS, however the UPS also has an integrated 1330 Joule MOV surge protector in it. If you think this integrated surge protector is an issue since I have a whole home protector, I can remove the UPS entirely. But then the computer would be susceptible to brown outs.

Really appreciate your help so far. It's a lot to visualize on how to fix my surge issues.

There is always a temptation to think that more is better, when often that is NOT true.

SPD 1 types are for service entry and type 2 at the panel. It is important to have the right types at the right place.

Here is a picture of a surge protector.

You will note a combination of inductors and capacitors.

AC circuits are not at all like DC circuits. AC has phase in terms of current and voltage through out the 360 degree cycle. Inductors and capacitors alter the phase relationships in opposite ways.

So if you have the wrong combinations then you can easily make matters worse. So it is perfectly possible by the wrong combination to make a spike worse due to un unfortunate misalliance of phase angles.

So it is ill advised to add additional surge protection in series. Type 1 and 2 are designed to be complimentary. So you need a type 1 at entry.

You should not be adding further surge protection.

I would use a good UPS unit on everything except the receiver and leave it at that.

If you end up replacing the receiver I would seriously consider separates so you you can protect fragile circuits with the UPS. With the large current and inductance on the power supplies of receivers all bets are off if you connect them to a UPS.

I think there is a good chance you have "over egged the cake" with all your protection devices and quite likely contributed to your problem.

 

[hutt132]

There is always a temptation to think that more is better, when often that is NOT true.

SPD 1 types are for service entry and type 2 at the panel. It is important to have the right types at the right place.

Here is a picture of a surge protector.

You will note a combination of inductors and capacitors.

AC circuits are not at all like DC circuits. AC has phase in terms of current and voltage through out the 360 degree cycle. Inductors and capacitors alter the phase relationships in opposite ways.

So if you have the wrong combinations then you can easily make matters worse. So it is perfectly possible by the wrong combination to make a spike worse due to un unfortunate misalliance of phase angles.

So it is ill advised to add additional surge protection in series. Type 1 and 2 are designed to be complimentary. So you need a type 1 at entry.

You should not be adding further surge protection.

I would use a good UPS unit on everything except the receiver and leave it at that.

If you end up replacing the receiver I would seriously consider separates so you you can protect fragile circuits with the UPS. With the large current and inductance on the power supplies of receivers all bets are off if you connect them to a UPS.

I think there is a good chance you have "over egged the cake" with all your protection devices and quite likely contributed to your problem.

Do you have a recommended UPS that doesn't have built-in MOV surge protection? Most consumer UPS I see only offer built-in surge protection.

 

[TLS Guy]

Do you have a recommended UPS that doesn't have built-in MOV surge protection? Most consumer UPS I see only offer built-in surge protection.

For a UPS I don't think that is an issue, as they are designed to disconnect your gear instantly from AC and go to battery when power is out of the set voltage requirements and will even shave voltage if it get too high and will let you know if the AC line is out of spec. so I would not worry about that.

I have always used nits from APC and found them very satisfactory.

 

[hutt132]

For a UPS I don't think that is an issue, as they are designed to disconnect your gear instantly from AC and go to battery when power is out of the set voltage requirements and will even shave voltage if it get too high and will let you know if the AC line is out of spec. so I would not worry about that.

I have always used nits from APC and found them very satisfactory.

I read that the shunt mode of MOVs shunts the surge to ground which could impact sensitive electronics. When the UPS switches to battery, the ground for devices on it is still tied to the outlet, so the shunted surge "dirties" the ground for all devices.