Stubborn Home Audio System Hum Problem

[bergwayne]

I have a Russound home audio amp. It hums terribly at low volume. When I plug the amp into a car AC/DC convertor with an extension cord the hum is gone and it works perfectly.

I have tried the following, nothing stops the hum except the car AC/DC convertor:
1) the 3 plug to 2 plug convertor to eliminate ground feedback issues
2) isolating every zone and source on the amp
3) disconnecting all of the sources to the amp
4) isolating every circuit in my house to see if I could locate an electrical problem
5) hooking the amp to different circuits in my house, with that circuit being the only one turned on at the time
6) connecting the 2 different grounds in my house, the electrical service and the cable/phone service
7) using the same extension cord setup that I used with the AC/DC convertor


I did have a lightning stike near my house a few weeks ago which blew out about $1000 of electronic equipment that has all been repaired.

Could it be that the power coming into my house has a problem? I am lost as to what else to try.

I'd appreciate any help. Thanks!

 

[dougg]

Check and clean Ground Connection outside.....

Check thre ground wire for a burnt separation. Take the Electric Panel cover off and check for loose / burned Connections. The Lightning strike could have caused hidden damage. NEC Code says the Telephone / cable ground should also be tied to your house ground, that is never the case!
Good Luck
Doug S.

 

[bergwayne]

By checking the ground for seperation, are you meaning at the service panel or in the amp?

Since I bypassed the ground by using a 2 prong plug (among other things), I thought I eliminated a grounding issue. Maybe not?

 

[dougg]

Check the Service Ground, end to end.

xxxxxxxxxxxxxxx dddddddddd

 

[highfigh]

I have a Russound home audio amp. It hums terribly at low volume. When I plug the amp into a car AC/DC convertor with an extension cord the hum is gone and it works perfectly.

I have tried the following, nothing stops the hum except the car AC/DC convertor:
1) the 3 plug to 2 plug convertor to eliminate ground feedback issues
2) isolating every zone and source on the amp
3) disconnecting all of the sources to the amp
4) isolating every circuit in my house to see if I could locate an electrical problem
5) hooking the amp to different circuits in my house, with that circuit being the only one turned on at the time
6) connecting the 2 different grounds in my house, the electrical service and the cable/phone service
7) using the same extension cord setup that I used with the AC/DC convertor


I did have a lightning stike near my house a few weeks ago which blew out about $1000 of electronic equipment that has all been repaired.

Could it be that the power coming into my house has a problem? I am lost as to what else to try.

I'd appreciate any help. Thanks!

Your house should have ONE ground. Any other devices used in the house should attach to that, at the point where they enter the house (called the point of demarcation, or demarc point) or as soon as possible once it's inside. Cable, Telco and satellite are all required to connect to the ground this way, as outlined by the NEC (Article 25, IIRC). If you have hum, it's either a lifted ground from the lightning (assuming it didn't hum before), a ground loop because of where the equipment is located and plugged in or the cable feed isn't grounded properly (extremely common). Unplug the cable feed from the first piece of equipment it's connected to and if the hum goes away, get an isolation adapter.

 

[bergwayne]

Thanks for the responses.

I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

It didn't hum before the lightning stike.

I hooked a new copper ground wire from a ground strip lug on the the service panel to the incoming copper water line, where my cable TV feed is gounded. If the service ground went bad, I would think I have corrected that problem. Am I correct? It still hums.

I think I've eliminated a ground loop possibility by using the 2 prong plug and also connecting the two main grounds to the same lug on the copper water line. Am I correct?

I unhooked the Cable TV main feed in my basement before it goes into my distribution center and it didn't help. Could it still be that my cable feed isn't properly grounded or have I eliminated that possibility?

I have unhooked the Cable TV source into my amp, I only have a CD player hooked up.

Any other suggestions? I am running out of ideas.

 

[TLS Guy]

Thanks for the responses.

I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

It didn't hum before the lightning stike.

I hooked a new copper ground wire from a ground strip lug on the the service panel to the incoming copper water line, where my cable TV feed is gounded. If the service ground went bad, I would think I have corrected that problem. Am I correct? It still hums.

I think I've eliminated a ground loop possibility by using the 2 prong plug and also connecting the two main grounds to the same lug on the copper water line. Am I correct?

I unhooked the Cable TV main feed in my basement before it goes into my distribution center and it didn't help. Could it still be that my cable feed isn't properly grounded or have I eliminated that possibility?

I have unhooked the Cable TV source into my amp, I only have a CD player hooked up.

Any other suggestions? I am running out of ideas.

You have an unusual problem.

As I understand, and please correct me if I'm wrong, if your amp has open inputs (nothing connected to it except speakers and the mains feed) it hums. If however you connect it via an inverter it does not. This occurs whether you amp is grounded or not.

I think if I have understood this correctly there are two possibilities.

1). The lightning strike has done damage to the neutral supply of your house. You need to have this checked by a professional.

2). The power supply of your amp has been damaged, by the lightening strike.

When connected to the mains, the voltage swings +60/-60 above and below neutral. When you supply it from an inverter, the amp is isolated from the mains supply and the inputs do not have a potential with respect to ground, only each other. So at peak voltage one pin is +60 the other -60. So the two powering situations are very different. I think it more than likely that the power supply is damaged. Take the amp to a neighbors and friends house and see if it hums there. If it does get it serviced.

 

[bergwayne]

Thanks for the advice. You did understand my problem correctly.

I'm not sure I can take it to a neighbors house because the outputs go through Russound keypads and then to the speakers. I'm not sure I can just connect it to speakers without the keypads, I'll have to experiment with that. If I can, that is a great idea that I hadn't thought of.

I almost sent it to Russound but after it worked perfectly on the inverter I thought the problem must be something wrong in my house. The Russound service guy thought it was a grounding issue in my house.

I'll keep trying and let you know if/when I get it figured out.

 

[TLS Guy]

Thanks for the advice. You did understand my problem correctly.

I'm not sure I can take it to a neighbors house because the outputs go through Russound keypads and then to the speakers. I'm not sure I can just connect it to speakers without the keypads, I'll have to experiment with that. If I can, that is a great idea that I hadn't thought of.

I almost sent it to Russound but after it worked perfectly on the inverter I thought the problem must be something wrong in my house. The Russound service guy thought it was a grounding issue in my house.

I'll keep trying and let you know if/when I get it figured out.

I did not realize this was part of a whole house system. They are the sort of systems I run miles and miles from.

I have been on the Russound site, and is typical of these sort of outfits, there is very sparse meaningful technical information, and no important details. I tried to watch one of their videos, but it locked up my computer, so obviously this is poor job, which is not encouraging.

I thought their website lousy, useless and entirely conceived by the marketing boys. However I have the impression that the switches communicate via the mains. Did I correctly glean that in the midst of all their garbage. If that is so, then those types of systems are a nightmare, and easily upset. They can lead to all of the problems you are experiencing and worse.

If I have gathered correctly that this system is using house wiring to send communication, then this part of your system goes to the top of the list as prime suspect.

If you have some speakers you can connect directly to the amp without going through the switches, go ahead and do it. I have a feeling the amp will not hum into speakers not part of the switching system. If it does not hum you have your answer and the service guy needs to sort it out.

 

[bergwayne]

TLS,

Yes it is a whole house system. I checked and it will be difficult to take the amp to a friends house because I would have to remove a keypad (I need it as a switch) , rewire the plugs involved, and redo the setup at the friends house. Not impossible, but difficult.

The keypads are wired with low voltage wiring from the amp, the keypads are switches which turn on the speakers to that zone and are capable of switching between the input sources. The speakers are fed from directly from the amp, the keypads turn on the speaker feed.

I don't thnk there is a kepad (switching system) problem becasue I have isolated each switch by disconnecting them all and then reconnecting one at a time. I get the same hum on each speaker pair no matter which keypad (switch) and speaker zone I reconnect.

I cannot get output to the speakers without the switch turning on that output so I cannot test whether I have speaker hum with out connecting a switch.

Any other suggestions?

Can you help me with what issues I have completely eliminated as the source of the problems through my various trials? For instance, does going to an ungrounded amp eliminate the possiblility of a ground loop? Also, could I still have a Cable TV ground problem? If the mains neutral was damaged, wouldn't this be showing up somewhere else besides this hum? I'm not too sure on these things.

 

[highfigh]

Thanks for the responses.

I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

It didn't hum before the lightning stike.

I hooked a new copper ground wire from a ground strip lug on the the service panel to the incoming copper water line, where my cable TV feed is gounded. If the service ground went bad, I would think I have corrected that problem. Am I correct? It still hums.

I think I've eliminated a ground loop possibility by using the 2 prong plug and also connecting the two main grounds to the same lug on the copper water line. Am I correct?

I unhooked the Cable TV main feed in my basement before it goes into my distribution center and it didn't help. Could it still be that my cable feed isn't properly grounded or have I eliminated that possibility?

I have unhooked the Cable TV source into my amp, I only have a CD player hooked up.

Any other suggestions? I am running out of ideas.

Get one of the testers in the photo. If the hot, neutral or ground have a problem, you'll see it. Don't pay more than about $6 for it- they sell them at all different hardware stores.

If your hum is there when the ground lift adaptor is on and you don't have any other equipment connected to the receiver other than the speakers (this means you need to unplug the CD player), it's in the receiver and most likely a bad filter capacitor. It's an easy fix but if that had gone in for service, it should have been found then.

 

[dougg]

Are You in the USA....

Quote:
I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

This i don't understand.
They should be a Bare #6 or 8 copper Ground wire run outside to a "Ground Rod" usally 8 feet deep. This is a code Requirment in the USA, has been for many Years. This is not the "Third" wire ground, run with the Service into the house from the street.
It does sound as if something is amiss since the Lightning strike. Do get an Electrican to look at your Elect. System.

 

[bergwayne]

Quote:
I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

This i don't understand.
They should be a Bare #6 or 8 copper Ground wire run outside to a "Ground Rod" usally 8 feet deep. This is a code Requirment in the USA, has been for many Years. This is not the "Third" wire ground, run with the Service into the house from the street.
It does sound as if something is amiss since the Lightning strike. Do get an Electrican to look at your Elect. System.

You are correct, that was a dumb statement on my part. I was thinking about the "third" wire, not the ground rod. I have checked the ground rod, it is intact.

 

[bergwayne]

Get one of the testers in the photo. If the hot, neutral or ground have a problem, you'll see it. Don't pay more than about $6 for it- they sell them at all different hardware stores.

If your hum is there when the ground lift adaptor is on and you don't have any other equipment connected to the receiver other than the speakers (this means you need to unplug the CD player), it's in the receiver and most likely a bad filter capacitor. It's an easy fix but if that had gone in for service, it should have been found then.

What is that tester called? Is it a "ground lift adapter"? I'm not sure what it connects to in my system. I need a little more help on that.

Is it just a tester for the power coming to the outlet? Its not easy to tell from the photo.

 

[bergwayne]

I reread the last posts, I think I understand now. The ground lift adapter is the 3 prong to 2 prong plug. The tester is a AC power tester that tests the outlet.

I'm up to $1100 in fixing my problems already, I'm trying to avoid filing an insurance claim since I have been claim free for 30 years and get a good rate on my insurance. My deductible is $1000. I just discovered one of my ice makers is making 6 cubes a night, it might have been ruined also.

I was hoping to get this fixed for $300 or so and keep my out-of-pocket to about $1400 and not file the claim.

I am faced with either calling an electrician to check the house wiring first or sending the amp in for repair which I was told will likely be at least $250 plus shipping. Which would you guys recommend I do first? Or do I need both?

Since the amp works perfectly with the DC/AC invertor, I'm having trouble pinning it on the amp.

Maybe I should just file the insurance claim and call in the pros to fix things and give up.

 

[TLS Guy]

TLS,

Yes it is a whole house system. I checked and it will be difficult to take the amp to a friends house because I would have to remove a keypad (I need it as a switch) , rewire the plugs involved, and redo the setup at the friends house. Not impossible, but difficult.

The keypads are wired with low voltage wiring from the amp, the keypads are switches which turn on the speakers to that zone and are capable of switching between the input sources. The speakers are fed from directly from the amp, the keypads turn on the speaker feed.

I don't thnk there is a kepad (switching system) problem becasue I have isolated each switch by disconnecting them all and then reconnecting one at a time. I get the same hum on each speaker pair no matter which keypad (switch) and speaker zone I reconnect.

I cannot get output to the speakers without the switch turning on that output so I cannot test whether I have speaker hum with out connecting a switch.

Any other suggestions?

Can you help me with what issues I have completely eliminated as the source of the problems through my various trials? For instance, does going to an ungrounded amp eliminate the possiblility of a ground loop? Also, could I still have a Cable TV ground problem? If the mains neutral was damaged, wouldn't this be showing up somewhere else besides this hum? I'm not too sure on these things.

Do you have a link to an online manual of what you have? Are you certain the key pads were wired in with low voltage wiring, as they do seem to have a system that avoids that?

Now the -ve terminal of an amp is connected to the ground plane. So any key pads or switches having a ground connection would create the ideal set up for a ground loop.

My instincts tell me that it something along these lines that is causing the trouble.

If you have an ohm meter, I would do the following. Disconnect the speakers from the amp, and see if any of the key pads or switches have a connection to ground. You can use the ground of any handy house electrical outlet to check a connection to ground.

If you find some, get hold of the installer and see if he can break them. Also if you could get a speaker connector from the installer and see if you can connect at least one speaker directly to a speaker output and see of you have hum. These types of investigations will shed light on what is going on.

 

[bergwayne]

TLS,

http://www.russound.com/pdf/MANUALS/CASeriesmanualR6.pdf

That is the manual for what I have. It is a CA 6.4i, which has 6 speaker zones, 6 keypads and 4 source inputs.

I'm pretty sure the wiring to the keypads is all low voltage.

Thanks for your help!

 

[TLS Guy]

TLS,

http://www.russound.com/pdf/MANUALS/CASeriesmanualR6.pdf

That is the manual for what I have. It is a CA 6.4i, which has 6 speaker zones, 6 keypads and 4 source inputs.

I'm pretty sure the wiring to the keypads is all low voltage.

Thanks for your help!

Yes, that system is all low voltage.

What is not mentioned is whether the grounds of the key pad unit and speaker switcher are connected to the cases. I assume these pads and switchers are screwed to grounded wall receptacles. You could confirm that with a continuity meter to see of the ground connectors are in continuity with case screwed into the receptacle. Then see if the receptacles they are screwed to are grounded. If they are you have multiple grounds all over the house which is begging for ground loop problems. The reason being, that because of the resistance of ground cables through out the house, grounds are never at the same potential. That sets you up for current flowing between grounds which causes hum.

I think you have a lot of detective work to do. If all else fails an isolation transformer to power your amp unit would likely solve the problem. However that would be a significant expense.

 

[bergwayne]

Whew! I thought I was out of detective work.

From what I gather it's your opinion that it's too early to be sending the amp in for repair.

While I ponder your last suggestion, I live a 100 feet away from a neighbor who is seldom home. When I see him in the next week or so I'm going to ask if I can run an extension cord over to see if using his house power stops my hum. Am I mistaken in that doing that should tell me a lot?

Several other questions:
So are you saying that even if my amp has the ground lifted (with the 2 prong adapter) a ground loop somewhere in my house could still cause hum? I thought I would have to connect the amp to a ground to get the hum.

The brown/white Cat 5 wire is a ground according to the Russound manual. So you are asking whether that ground is connected to a ground going back to the mains if I understand what you are getting at?

 

[highfigh]

Quote:
I searched the service ground as best I could but couldn't find anything wrong. It's an underground feed from the street so it is not all accessible.

This i don't understand.
They should be a Bare #6 or 8 copper Ground wire run outside to a "Ground Rod" usally 8 feet deep. This is a code Requirment in the USA, has been for many Years. This is not the "Third" wire ground, run with the Service into the house from the street.
It does sound as if something is amiss since the Lightning strike. Do get an Electrican to look at your Elect. System.

The ground is for the hardware in the house, not the service feed. The third wire is the neutral and the other two carry 120VAC, on different phases (180 degrees opposed), so when a device is wired to both, the total potential (voltage) is 240VAC.

I agree that having an electrician check out the house is a good idea, especially after a lightning strike.