Major interference with Receiver in home Theater

[Jojo459sp]

Hi Friends,

I've spent the last couple of days all over the forums looking for answers and so far I've come up empty handed. I'm getting major interference through my speakers with my home theater that sounds almost like rapid morse code. It's not a constant humming, just an intermittent 10-15 rapid hums that comes and goes every few seconds. The weird thing is that I've used this system for months without any problems. Here is a quick overview of what I've tried so far to help eliminate or at least pinpoint the noise as well as some of the symptoms:

- I only hear the sounds when my Denon AVR-S920 is on (I have a 7.1 setup with a custom sub)
-I've got all my components passing through the Denon for picture/sound (Xbox One S, PS4, Amazon Fire)
- The sound gets maybe10-15% quieter if I disconnect my Sub
-The sounds gets maybe 5% quieter when I disconnect the HDMI cables from my my Denon (coming from Xbox and PS4) No affect when removing the Amazon Fire
-I still hear the sounds when everything is disconnected except for the speakers so it's definitely my receiver that is picking up the noise
- I've checked all connections, reconnected EVERYTHING
-I've tried adding ferrite chokes to several of the power cords, speaker wire and even HDMI (no help)
-The interference does NOT get louder or softer when I change the volume on my receiver.
-The interference DOES randomly get louder and softer on it's own.
-I've toyed around with the outlets, to eliminate any ground loop issues. (No help)
- I've kept speaker wires away from power cables and again, moved everything around

Now here is the most interesting part. The person who lives behind me has 3 giant HAM radio towers. I do get interference from that when he uses it maybe once a month, but I know that's him because I can actually hear him talking through my speakers. It's crazy and I don't know how to get rid of it. I'm assuming, my current problem is related to the same thing, but I'm not sure. When I hear my neighbor, I get it through my computer speakers. Not the case with his morse code sounding interference. It's been happening for 3 days straight. I'm really at a loss here...any suggestions?? I can add some audio if anyone thinks that'll help.

 

[shadyJ]

It sounds like his transmitter is bleeding into your system. He may be using an amplifier that is way out of spec. You are going to have to talk to your neighbor.

 

[TLS Guy]

This may be interference and may be not.

The best test is to ask a friend if you can test your receiver at a place remote from the ham radio operator.

Do you hear this interference on headphones with the speakers disconnected?
I ask this as interference from radio transmitters is usually picked up by speaker leads, and fed back to the voltage gain circuits of the power amps via the negative feedback circuits.

If you don't hear this though headphones with the speakers and everything else disconnected then that it your answer.

If you can not get the cooperation of your neighbor, then a solution is to get some ferrite aerial rod and cut into 2' or so length. Wind solid 12 AWG copper wire round it, 10 turns is about optimal. Make one for each speaker. Now connect each one in series with the +ve speaker wire right at the receiver.
That will generally stop this type of interference.

If you have this problem at a remote location then the receiver is failing with an unstable circuit.

 

[mtrycrafts]

Welcome to AH.

May also want to ask your neighbor if he could shut his ham off totally as a test and see if there is a difference.
Is this a new ham setup or been there for a while well before the interference you are getting?

ps. if he cooperates, perhaps you could have your system on hopefully still humming then call him to turn it off.

 

[Jojo459sp]

Thanks everyone for all the replies. Sorry I'm a little late to respond! I did take the advice of talking to my neighbor and that was the best course of action. He turned out to be a super nice guy who was more than willing to help. He gave me a filtered surge protector to try which he uses in his own house with all of his equipment. Turns out we have a mutual friend that is going to stop by an help this weekend. I think we've pinpointed the problem on both ends. We are going to do some testing this weekend but I'm confident my problems are just about over! There is a lot more to this story, so if anyone is interested, I'd be happy to share more details. Maybe I can help out people with similar issues in the future


Thanks again!!

 

[TLS Guy]

Thanks everyone for all the replies. Sorry I'm a little late to respond! I did take the advice of talking to my neighbor and that was the best course of action. He turned out to be a super nice guy who was more than willing to help. He gave me a filtered surge protector to try which he uses in his own house with all of his equipment. Turns out we have a mutual friend that is going to stop by an help this weekend. I think we've pinpointed the problem on both ends. We are going to do some testing this weekend but I'm confident my problems are just about over! There is a lot more to this story, so if anyone is interested, I'd be happy to share more details. Maybe I can help out people with similar issues in the future


Thanks again!!

Please share in the greatest of detail. You are not the first to post about this problem.

I would say though that I would be surprised if this turns out to be transmitted through the AC line. If it is then there would have to be something highly irregular for a start. If it is the case you both need to check your house grounding very carefully and make sure it meets or exceeds code.

 

[Jojo459sp]

I will definitely share all the details. Once we are confident we got to the root of the problem this weekend I’ll post all the details of what we did and how we fixed it. I actually just recently had an electrician come in to make sure my stuff is up to code ironically. But we are going to test it all againn just in case

 

[slipperybidness]

Thanks everyone for all the replies. Sorry I'm a little late to respond! I did take the advice of talking to my neighbor and that was the best course of action. He turned out to be a super nice guy who was more than willing to help. He gave me a filtered surge protector to try which he uses in his own house with all of his equipment. Turns out we have a mutual friend that is going to stop by an help this weekend. I think we've pinpointed the problem on both ends. We are going to do some testing this weekend but I'm confident my problems are just about over! There is a lot more to this story, so if anyone is interested, I'd be happy to share more details. Maybe I can help out people with similar issues in the future


Thanks again!!

Yup, talking to the neighbors is always a good thing! I know all of my neighbors, and several of the people living all up and down my street too.

It really helps to keep the neighborhood safe when you know who is a regular and who may be a shady character.

 

[Speedskater]

Many Hams have or know other Hams that have the skill, knowledge and equipment to troubleshoot interference. No Ham would transmit every few seconds 24 by 7 so it's not his transmitter, go over and ask for his help.

It could be something as simple as your doorbell transformer, or a burnt-out CFL bulb that you think is turned off.

Jim Brown being both past Audio Engineering Society co-chair on EMR/RFI interference and a Ham radio operator has about 50 papers, many on interference:
http://www.audiosystemsgroup.com/publish.htm.

 

[highfigh]

Hi Friends,

I've spent the last couple of days all over the forums looking for answers and so far I've come up empty handed. I'm getting major interference through my speakers with my home theater that sounds almost like rapid morse code. It's not a constant humming, just an intermittent 10-15 rapid hums that comes and goes every few seconds. The weird thing is that I've used this system for months without any problems. Here is a quick overview of what I've tried so far to help eliminate or at least pinpoint the noise as well as some of the symptoms:

- I only hear the sounds when my Denon AVR-S920 is on (I have a 7.1 setup with a custom sub)
-I've got all my components passing through the Denon for picture/sound (Xbox One S, PS4, Amazon Fire)
- The sound gets maybe10-15% quieter if I disconnect my Sub
-The sounds gets maybe 5% quieter when I disconnect the HDMI cables from my my Denon (coming from Xbox and PS4) No affect when removing the Amazon Fire
-I still hear the sounds when everything is disconnected except for the speakers so it's definitely my receiver that is picking up the noise
- I've checked all connections, reconnected EVERYTHING
-I've tried adding ferrite chokes to several of the power cords, speaker wire and even HDMI (no help)
-The interference does NOT get louder or softer when I change the volume on my receiver.
-The interference DOES randomly get louder and softer on it's own.
-I've toyed around with the outlets, to eliminate any ground loop issues. (No help)
- I've kept speaker wires away from power cables and again, moved everything around

Now here is the most interesting part. The person who lives behind me has 3 giant HAM radio towers. I do get interference from that when he uses it maybe once a month, but I know that's him because I can actually hear him talking through my speakers. It's crazy and I don't know how to get rid of it. I'm assuming, my current problem is related to the same thing, but I'm not sure. When I hear my neighbor, I get it through my computer speakers. Not the case with his morse code sounding interference. It's been happening for 3 days straight. I'm really at a loss here...any suggestions?? I can add some audio if anyone thinks that'll help.

Turn off any cell phones in the house. If it's groups of three short tones, it's something I have heard through my computers over the years, with different phones.

Add the audio.

 

[Jojo459sp]

Many Hams have or know other Hams that have the skill, knowledge and equipment to troubleshoot interference. No Ham would transmit every few seconds 24 by 7 so it's not his transmitter, go over and ask for his help.

It could be something as simple as your doorbell transformer, or a burnt-out CFL bulb that you think is turned off.

Jim Brown being both past Audio Engineering Society co-chair on EMR/RFI interference and a Ham radio operator has about 50 papers, many on interference:
http://www.audiosystemsgroup.com/publish.htm.

Hi Speedskater - I should have been more clear in my original note. The Interference ONLY happens when they are broadcasting. It's very clear that the interference is directly related to the HAM radio. I can hear him clear as day and I can hear the morse code clear as day as well. If you read further in this thread, you'll see that I updated it and said that I already went over to talk to him and there was a happy ending. Without a doubt, talking to him was the best thing I could have done. He gave me some equipment to add to my system and we are going to do some testing with his equipment and my equipment this Sat.

 

[Jojo459sp]

Turn off any cell phones in the house. If it's groups of three short tones, it's something I have heard through my computers over the years, with different phones.

Add the audio.

Thanks highfish. I updated this thread to say that we have the problem narrowed down and after this weekend when we do some testing I'm confident that the problem will be solved with the help of my neighbor. I'll post all the details of what we've done so far and what we do This weekend to eliminate the problem. I think it'll be very helpful for anyone dealing with a similar problem.

 

[Speedskater]

Then definitely get the Ham involved. Almost all modern Ham equipment operates within spec but all hi-fi equipment is not as well designed.

Jim Brown has papers on this exact hi-fi problem. like:

"RF Interference in Audio Systems"
http://www.audiosystemsgroup.com/AES-RFI-SF08.pdf

 

[Jojo459sp]

Then definitely get the Ham involved. Almost all modern Ham equipment operates within spec but all hi-fi equipment is not as well designed.

Jim Brown has papers on this exact hi-fi problem. like:

"RF Interference in Audio Systems"
http://www.audiosystemsgroup.com/AES-RFI-SF08.pdf

Thanks for the link, I'll check it out. He's coming over this Saturday with another Ham operator to help troubleshoot. There's more to the story that I haven't talked about yet, but he's getting some interference from my neighborhood somewhere (possibly me) too. We are both invested in helping each other out. He's been really great about everything so far. Again, I'm glad I decide to talk him directly instead of trying to solve the problem on my own. By the way, he's not just a Ham enthusiast, he runs contests out of his home (which is actually a business) has 3 giant towers, dozens of stations..etc. He makes and sells equipment as well. He clearly knows his stuff!

 

[William Lemmerhirt]

My old friend/neighbor used to run Ham radio(rest his soul). I’ll never forget the first time he woke me up with the sound of his voice in my subs! We tried every ferrite ring and do-dad we could think of. In the end , the thing that made the biggest difference was good shielded cables. My son also used to get the weird Morse code thing too, when he hooked up his phone or laptop via 3.5 to stereo pair to his receiver. Cable upgrade fixed that too. Hope you guys get this ironed out. I know how frustrating it can be.

 

[TLS Guy]

Thanks for the link, I'll check it out. He's coming over this Saturday with another Ham operator to help troubleshoot. There's more to the story that I haven't talked about yet, but he's getting some interference from my neighborhood somewhere (possibly me) too. We are both invested in helping each other out. He's been really great about everything so far. Again, I'm glad I decide to talk him directly instead of trying to solve the problem on my own. By the way, he's not just a Ham enthusiast, he runs contests out of his home (which is actually a business) has 3 giant towers, dozens of stations..etc. He makes and sells equipment as well. He clearly knows his stuff!

That is bad news. If those are licensed powerful pro transmitters and not low power ham transmitters, your problem is unlikely to be completely solvable. Domestic equipment almost always has these type of issues in close proximity to commercial radio towers and TV towers.

My advice though is to first concentrate on the speaker leads. In my experience, and I've had quite a bit of it, the speaker leads are the major culprit. This seems at first counter intuitive. However the speaker leads are connected to the early high gain stages via the negative feedback circuit. The base emitter junctions in the transistors/ICs, make the perfect detector for radio signals, and function just like an old crystal radio.

 

[Speedskater]

We had regular hi-fi equipment operating in the studio just hundreds of feet from the most powerful FM broadcast transmitter in the US.

 

[TLS Guy]

We had regular hi-fi equipment operating in the studio just hundreds of feet from the most powerful FM broadcast transmitter in the US.

I can believe that. A lot depends on the design. Quad amps have an RF blocking circuit in the output to the speaker terminals. RF can also get in through the high gain stages, especially phone inputs.

 

[Jojo459sp]

My old friend/neighbor used to run Ham radio(rest his soul). I’ll never forget the first time he woke me up with the sound of his voice in my subs! We tried every ferrite ring and do-dad we could think of. In the end , the thing that made the biggest difference was good shielded cables. My son also used to get the weird Morse code thing too, when he hooked up his phone or laptop via 3.5 to stereo pair to his receiver. Cable upgrade fixed that too. Hope you guys get this ironed out. I know how frustrating it can be.

Thanks, this is good to know! Any idea what type of cables? I may need to upgrade mine with better shielded cables

 

[Jojo459sp]

That is bad news. If those are licensed powerful pro transmitters and not low power ham transmitters, your problem is unlikely to be completely solvable. Domestic equipment almost always has these type of issues in close proximity to commercial radio towers and TV towers.

My advice though is to first concentrate on the speaker leads. In my experience, and I've had quite a bit of it, the speaker leads are the major culprit. This seems at first counter intuitive. However the speaker leads are connected to the early high gain stages via the negative feedback circuit. The base emitter junctions in the transistors/ICs, make the perfect detector for radio signals, and function just like an old crystal radio.

Good to know! Looking at the speaker leads will be first on my list then! Thanks, that’s good advice