Major interference with Receiver in home Theater

[TLS Guy]

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

I would try the RF choke first if it proves to be the cables. The one I outlined has worked for me in the past.

Shielded cables are not suitable as speaker cables. If it comes to that you will have to run our speaker cables in metal conduit.

 

[Speedskater]

The first thing is to let the Hams identify the problem. Trying random curies requires a lot of luck. It's best to fix the problem at it's source. But if that's not possible then different interference frequencies require different ferrite material and different cable shields.

 

[slipperybidness]

I would try the RF choke first if it proves to be the cables. The one I outlined has worked for me in the past.

Shielded cables are not suitable as speaker cables. If it comes to that you will have to run our speaker cables in metal conduit.

I didn't know that, why is shielded cabling a problem for speaker cables?

 

[Speedskater]

A pro audio guy that does large stadium installations has that on occasion he as had problems with shielded (conduit) speaker cable runs. The added capacitance upset the amplifiers. I doubt that it would be a problem with most hi-fi amplifiers. A good plan for speaker cables is a Twisted Pair. With one twist about every 3 or 4 inches.

An RF choke is an over simplification. Jim Brown has a 66 page paper on ferrite chokes. You need to think about the correct material, the correct placement and the number of turns.

 

[mtrycrafts]

A pro audio guy that does large stadium installations has that on occasion he as had problems with shielded (conduit) speaker cable runs. The added capacitance upset the amplifiers. I doubt that it would be a problem with most hi-fi amplifiers.
...

I would think that large stadium speakers need long runs of speaker cables? If so, the capacitance certainly add up in a hurry. Naim amps used to destroy themselves with high cap cables in home setups. They needed Naim speaker cables or else....

 

[Speedskater]

I mis-remembered, this is what he wrote:

Now for those that actually would like to measure the difference, use a concrete floor that is poured over a corrugated steel deck..................

Guess what, the capacitance of the floor is well coupled to the power amplifiers chassis and with some amplifiers you will see burst of oscillation that decrease as you lift the cable. Twisting it will not have any effect.
....................................
Yes I have had systems where some of the amplifiers feeding a loudspeaker array had issues and others of the same model and manufacture date did not.

 

[Peter Sarnosky]

Any updates on this thread?
I am having a similar issue with a new Denon X2300 that replaced an Onkyo that did not have this issue. Nothing else was changed
In this case I am the generator of the noise It must be the AVR. I am thinking of grounding the chassis (3prong) and have asked Denon for some input

Thx. Peter

 

[TLS Guy]

Any updates on this thread?
I am having a similar issue with a new Denon X2300 that replaced an Onkyo that did not have this issue. Nothing else was changed
In this case I am the generator of the noise It must be the AVR. I am thinking of grounding the chassis (3prong) and have asked Denon for some input

Thx. Peter

We need to know much more about your system. It sounds as if you have a ground loop. We need to know everything connected to that receiver and how. Also we need to know the details of any cable, satellite and Ethernet connections. We need every last little detail to help you with these problems. Adding a ground will more likely than not make matters worse.

 

[Jojo459sp]

Any updates on this thread?
I am having a similar issue with a new Denon X2300 that replaced an Onkyo that did not have this issue. Nothing else was changed
In this case I am the generator of the noise It must be the AVR. I am thinking of grounding the chassis (3prong) and have asked Denon for some input

Thx. Peter

I just realized I never came back and updated my thread. Sorry gang! I have completely eliminated all interference. I’m not exactly sure what did it, I think maybe it was a combination of things. I took an entire Saturday and basically started over with rewiring everything which was a massive pita! I added shielded cable wire to my speakers, added banana plugs, made sure all my connections were clean and added a filtered surge protector (actually two total). I also added rf chokes to all my rear speakers. I noticed I had one connection on my receiver that wasn’t as tight as it should be so I’m sure that added to my issues. Anyway, I’m not sure if you are having similar problems or not but there are some ideas for you. After talking to my ham radio operator neighbor, he believed the filtered surge protector would do the trick. I have a feeling that was the biggest help but it’s just a guess. Good luck bud, let me know if you have any questions or if I can help out in any way

Joe

 

[Peter Sarnosky]

Speaker FL ,FR ,RL, RR, C, and sub
HDMI IN. Playstation, (not used much), Apple TV, Fiber optic cable box. Fiber Optics terminated at entry panel then RG6 , wire FM antenna (not it, started with this completely disconnected.
HDMI out to TV And this unit is on DHCP router, Apple Airport Extreme. That is it.
As stated above with the Onkyo there were zero issues and I usually run around 1200w on SSB voice, 50w on digital modes, no difference using low power 50w.
I am suspicious of some common mode current on the line. There are no ground loops in the ham shack all equipment single pointed to two ground rounds outside. All entry panels properly grounged etc. i have been very meticulous about this.
Was thinking about shielded speaker wire but if there is no chassis ground where would the shield terminate ?

Thanks for reading this. Also looking at a 20a line conditioner?
I also tried clamp on ferrite on the AC line input and wrapped one speaker wire (for testing) with a torroidal core. No joy.

FYI the Denon 2300 is a two prong plug

Peter

 

[Peter Sarnosky]

Thanks Joe, copy all that
I think a line cconditioner is in order

Peter

 

[TLS Guy]

Thanks Joe, copy all that
I think a line cconditioner is in order

Peter

First of all what is the nature of the interference you are experiencing?

Line conditioners seldom help this type of problem.

Disconnect everything except speakers connected to your receiver and report back the effect of each disconnect.

When there is nothing connected to your receiver except the AC and the speakers but NOT the sub, do you hear any interference?

These are essential pieces of information required to guide you.

 

[Peter Sarnosky]

I will do that and get back on later, my trusty assistant is out shopping.
What I have is static interference during digital transmissions and voice bleed in during phone HF ops (my voice) I will unplug everything (including sub) but the front , rear, center and see what I get.
I initially thought that maybe my speaker wires were becoming antennas but that is doubtful as using them with the other AVR did not exhibit any issues.

Thanks

Peter

 

[Peter Sarnosky]

Test results with above conditions, hum static is still on the system when transmitting.
It is not affected by the volume control on the AVR.

 

[TLS Guy]

Test results with above conditions, hum static is still on the system when transmitting.
It is not affected by the volume control on the AVR.

If that is so and you have no inputs connected, no Ethernet and no cable or antennae connected, then you either have a faulty AVR or a strong source of radio frequency interference.

Major sources of RF interference are LED light bulbs and light dimmers of the SCR type.
Unfortunately modern homes are awash in RF, with both the above mentioned sources massive sources of RF. Home electronics are very poor rejectors of RF. This needs to change in the design of AV equipment especially receivers and pre/pros.

 

[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.

Is this sound in groups of three pulses, like ... ... ... ...? Where is your cell phone when this happens? I have heard the same sound when my old phone was near my computer.

 

[highfigh]

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

Was the building shielded?