Electrical options....advice please....

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  • treitz3
    treitz3 Posts: 19,029
    edited January 2008
    Steve, I thought I had a couple of AM radios used for camping around here somewhere but I can't find them, so I will have to go get an el'cheapo just to run your test [not a problemo].

    What I need to do is get an oscilloscope and find out what coming into the house. The electric company gave me the runaround all day Friday and I was able to leave a message with one of their engineers. No call back.

    It may just boil down to that [2 separate repairs], but I'm still in it with Portrait Homes to get someone to come out for warrantee work [since last April] and I'll be damned if I'm gonna pay an electrician some $85.00 an hour to NOT guarantee me that he can eliminate the issue. That would just be like throwing $400.00+ into the lottery "hoping" for a return and I don't have $$$ to just throw around like that, I'd rather spend it on new gear. Portrait Homes electrical subcontractor wants me to "prove it" to them too.

    This all goes back to getting an oscilloscope and being able to prove it to them. Until then, I'll do the AM radio thing.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • ShinAce
    ShinAce Posts: 1,194
    edited January 2008
    If you have some spare electronics parts, you can rig a scope using your sound card.

    http://www.ledametrix.com/oscope/index.html
    You'll want to change the resistor values accordingly (117 VRMS = 165 volts peak).
    Keep in mind your sample rate is limited.

    The notch filter I use for my stereo is a simple 7 amp model and cost me 5 $ (good old surplus). Here's a start:
    http://www.sphere.bc.ca/test/acfilters.html
    google "EMI line filter"

    This will be easier, and cheaper than trying to get a trace of your power line. Plus if it works, you already paid the deposit and get to use it.

    Best of luck.
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  • disneyjoe7
    disneyjoe7 Posts: 11,435
    edited January 2008
    Yes until you know for sure what's the source noise line or air, this issue as is be a lottery call. Just the fact you changed the power around it was a lottery call in the end.

    Speakers
    Carver Amazing Fronts
    CS400i Center
    RT800i's Rears
    Sub Paradigm Servo 15

    Electronics
    Conrad Johnson PV-5 pre-amp
    Parasound Halo A23
    Pioneer 84TXSi AVR
    Pioneer 79Avi DVD
    Sony CX400 CD changer
    Panasonic 42-PX60U Plasma
    WMC Win7 32bit HD DVR


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  • ShinAce
    ShinAce Posts: 1,194
    edited January 2008
    p.s. If all else fails, try grounding the case of your equipment with your hand and listen to it like that. ;)
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  • treitz3
    treitz3 Posts: 19,029
    edited January 2008
    ShinAce wrote: »
    p.s. If all else fails, try grounding the case of your equipment with your hand and listen to it like that. ;)
    No difference, tried it before and just for **** and giggles, tried it again. No difference when a dedicated ground is installed either, with or without all chassis grounds tied together or not.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • bigyank
    bigyank Posts: 224
    edited January 2008
    Any UPS available big enough to run a radio of any kind?

    Yank
    Polk Monitor 7
    Polk Atrium 55
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  • bikezappa
    bikezappa Posts: 2,463
    edited January 2008
    I don't understand why you can't use an isolation transformer to filter RF in the electric line. You buy one, plug it into the out let and plug the amp into the isolation transformer.

    You need a scope.
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  • ShinAce
    ShinAce Posts: 1,194
    edited January 2008
    The noise source has not been located, so how do you know it's RF on the power line? An isolation transformer is expensive. The equipment already has a transformer in it to start with; what exactly are you going to be isolating?

    BTW, I was joking when I said ground the equipment with your body. Would be funny if it did something.
    "Honey, lean with your hand here...okay...now stay like that"
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  • treitz3
    treitz3 Posts: 19,029
    edited January 2008
    Man, I've tried everything whether it sounds crazy or not. I've even tried hooking the rig up to my power generator....hehe, that just introduced more noise :rolleyes:. If it comes down to it, I might consider one like this...

    http://www.rdlnet.com/product.php?page=167

    http://www.rdlnet.com/pdf/Data_Sheets/tx-at1.pdf

    But before I go blow good money I want to find out what is causing this. A simple notch filter might just do the trick for less than what I blow on the cost of lunch at MickyD's. I just need to find out what's causing it.

    BigYank, no UPS. I'll just get a battery powered / plug in AM radio.
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • treitz3
    treitz3 Posts: 19,029
    edited January 2008
    bikezappa wrote: »
    You need a scope.
    You nailed it. Let me ask you guys this. If I can't get a hold of one, is there a scope that you know of that isn't 3K or some **** that I can use for this application. I remember back when I was in the industry, hand held scopes that weren't too god awfully priced. Any recommendations?

    1K or less? w/memory? Dual trace?
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • ShinAce
    ShinAce Posts: 1,194
    edited January 2008
    Post 63.

    You could use the computer to fourier analyze the input and ignore the 60 Hz fundamental, yielding the noise signature.

    The only problem is the limited frequency response. It is a good place to start, nonetheless.

    edit: might I suggest using 3.3 megaohm resistors instead of the 18K ones. Replace the 82K with 10-18K. All 1/4w.
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