EMI Issue

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  • JeremyG
    replied
    Originally posted by stuofsci02
    Plugging your stuff into another circuit may or may not isolate the pop. If the other circuit shares the same 120V to Neutral leg of the 240V feeder then the pop will still be present (circuit breakers do not filter electrical noise). You will need to make sure you test by running off the other leg of the 240V. This will be the breaker that is directly above or below the breaker your stuff is currently on.

    I doubt a ceiling fan has enough EMI to create a pop on your speakers. I am betting you have an old deteriorating switch that is causing a small Arc when you turn it on and off. Does the pop happen when you turn the fan on from the light switch, or when you turn it on from the fan itself?

    Cheers,

    Stuart
    Well, since the pop goes away when I disconnect the RCA's from the UPA, I can't imagine it would still be coming from the wall internal to the amp. The circuit I used to test the amp (using an extension cord) was a kitchen GFCI breaker on the opposite side of the panel. Don't know if they're on the same leg or not.

    I've left the wall switch on, and turned the fan motor on/off via the pull chain, and the pop is still present. Funny thing is, when the light kit is switched on by its pull chain, the pop goes away even when the fan motor is turned on/off as well.

    Guess the thing to do is build some cables. I've got some RG-6 Quad shield in the garage, and I just need to go to PE and find connectors that fit the OD/ID. Should be the cheapest route. Man, I wish I could leave this alone!

    Thanks, guys!!!

    Jeremy

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  • stuofsci02
    replied
    Plugging your stuff into another circuit may or may not isolate the pop. If the other circuit shares the same 120V to Neutral leg of the 240V feeder then the pop will still be present (circuit breakers do not filter electrical noise). You will need to make sure you test by running off the other leg of the 240V. This will be the breaker that is directly above or below the breaker your stuff is currently on.

    I doubt a ceiling fan has enough EMI to create a pop on your speakers. I am betting you have an old deteriorating switch that is causing a small Arc when you turn it on and off. Does the pop happen when you turn the fan on from the light switch, or when you turn it on from the fan itself?

    Cheers,

    Stuart

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  • whoaru99
    replied
    Originally posted by JeremyG
    Maybe I should stop over analyzing and just turn the fan on/off when the music is off!

    Jeremy
    That is a reasonable solution.

    It's funny how we obsess on these things. It's like "I know this will make a pop, so let's keep doing it to annoy myself." :B

    I'd also consider trying some different cables from a brand with known good shielding. There are many good cable stock providers, Belden, Canare, Mogami, etc. if you wanted to do your own.

    First option seems most foolproof though.

    Leave a comment:


  • JeremyG
    replied
    Thanks gents!!! :T

    The pop is present when the amps are run off of a different circuit. Definitely means the cable is an antenna. I think I'll order some ferrite beads from Allied to check (they're cheap).

    I'm using RCA's from Best Buy, their Dynex brand, I think. The cheapest they carry. Don't know how they're constructed. Maybe like RG-58/59? I too was wondering if the shielding or terminations weren't up to par. Since I terminate wiring in aircraft I probably have the skill to build my own. Guess Parts Express will be getting some business.

    I think changing the fan is too big an offense to attempt. I did wonder about dropping the motor and lining it with MuMetal or another type of shielding (aluminum foil?) Probably create a heat/fire issue, though.

    Thinking out loud at this point, but since both the AVR and the UPA don't have ground pins in the IEC connector, could this be a ground potential issue? The popping is attenuated when the RCA's are connected at both ends. We bond everything at work, so this is an issue for me. Guess I'll alligator clip the two together to check. Maybe the RCA shielding isn't providing enough shield ground path.

    Maybe I should stop over analyzing and just turn the fan on/off when the music is off!

    Jeremy

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  • whoaru99
    replied
    What sort of interconnects are you using and what's the shielding configuration of them?

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  • Kevin P
    replied
    Try plugging your system (at least the amps) into a different house circuit--use an extension cord if necessary--and see if you still get the pop. If you do, it's probably being picked up "off the air". If not, it's being transmitted thru the house wiring.

    If it's the house wiring, try a good power conditioner or have an electrician run a new circuit to your components. Otherwise, you could try ferrite beads on your interconnects and power cords, or get a different fan (some models may be more prone to EMI than others). The reason the light doesn't cause the pop is because the light isn't an inductive load.

    Leave a comment:


  • JeremyG
    started a topic EMI Issue

    EMI Issue

    Hope someone can help me, I'll try and explain this as easily as I can. My system is a 46" LCD, AppleTV, Sony Blu-ray, Marantz SR7001, Emo UPA-2, BFD, Crown XLS-602. It has been found that turning on the overhead fan in my living room (where the stereo is) produces a pop in the left and right mains. They are powered off of the UPA-2. The center is powered off the Marantz. There is no pop present in the center channel. I disconnected all components in turn to isolate anything. I separated the power cords from all components from the RCA's connecting the Marantz to the UPA (neither has balanced connectors available). Also plugged the UPA into the wall (normally plugged into a surge protector-yes I know Emotiva says to plug it straight in.) Disconnected the RCA's from the UPA, and the pop goes away. Disconnected the RCA's from the Marantz, and the pop is amplified. So this pretty much means the RCA cables are acting like an antenna. I wiggled the connectors on each end to make sure the shielding wasn't damaged, and the cables check good with a meter. Now here's the kicker: the overhead fan has a light kit, and when the light kit only is switched on, it does not produce the pop. It is only when the fan motor is switched on. So... I'm out of any ideas. Does anybody have any? Thanks!!!

    Jeremy
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