Where are the capacitors?

Discussion in 'Home Theater Projects' started by Steve Elias, Feb 5, 2004.

  1. Steve Elias

    Steve Elias Stunt Coordinator

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    I have an itch to try my hand at a popular DIY speaker project that calls for the following capacitors, resistors, and inductors:

    3.4 uf capacitor
    4.7 uf capacitor
    8.5 uf capacitor

    47 ohm/5W resistor
    5 ohm/5W resistor

    0.25 mH inductor (iron core)
    0.83 mH inductor (iron core)
    1.5 mH inductor (iron core)

    Where can I find these parts? So far I've tried Madisound, SpeakerCity, North Creek, Adire, Parts Express, and one other site whose name I can't recall at the moment. I've found 4.7 uf capacitors and 1.5 mH (air core?)inductors, but that's it so far.

    How dangerous (sound changing) is it to merely get close? For instance, an 0.82 inductor rather than a 0.83 inductor? Is it better to be a little over or a little under? Also, I'm thinking of using air core inductors instead of iron core. Does this seem foolish?

    Just for fun, can you identify the fairly popular kit I plan to build? Hint: Scan Speak drivers.

    Thanks for any guidance you can offer. In the meantime, I'll continue my search.

    Steve
     
  2. ThomasW

    ThomasW Cinematographer

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    You can parallel caps together to create any value you want.

    You can series/parallel resistors to create the needed value.

    Yes 0.82 is close enough.

    Iron core can saturate and then ring. But if the power handling of the woofer is fairly low; you can use a iron core, because the woofer would be over driven before the iron saturates.

    Since the inductors are fairly small values go with air core.
     
  3. Luitz

    Luitz Stunt Coordinator

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  4. Steve Elias

    Steve Elias Stunt Coordinator

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    Thanks Thomas for the info. I'll try to avoid a series approach for the moment, but it's good to know that I can fall back on that solution. Also, thanks for the iron core explanation. I have found handwound copper aircore inductors in whatever value I need at Taylor Speakers, but I'm still working on the capacitors and resistors.

    Luitz,
    My first thought was Solen, but so far I have only found a couple (three?) of the items on my shopping list at Solen retailers. I'll search through their catalog more thoroughly, however. Thanks.

    Another question: Does it matter if I mix and match different brand capacitors? I assume it isn't a big deal as long as they share the same material components (copper to copper, and so on) but then again, I now very little about crossovers and electronics.

    Thanks again.

    Steve
     
  5. ThomasW

    ThomasW Cinematographer

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    PaulT Supporting Actor

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    Dave Poehlman Producer

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    I know Madisound will "roll back" inductors to whatever value you want for a small fee.
     
  8. Steve Elias

    Steve Elias Stunt Coordinator

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    Thanks everyone, for the help.

    ThomasW,
    Thanks for clearing things up for me - I had just started to read about a series crossover option for the speaker I'm considering and now I understand better. Also, thanks for the additional advice.

    PaulT,
    Thanks for the link. I'll explore after I finish here.

    Dave,
    Thanks for the tip. Since my last post I've also found that Sonic Craft and Taylor Speakers will do so as well. One supply problem/decision made.
     
  9. Danny Richie

    Danny Richie Stunt Coordinator

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    Steve,

    FYI, we have all of that in stock.

    We have those cap values in Axon poly caps and in Sonicaps. I can also measure through a bunch of them to give you matched pairs and values that swing slightly one way or another.

    For instance, I know I have a bunch of 8.2 uF Sonicaps that measure out as 8.5's.

    No additional charge for that service either.

    Resistors are Mills 10 watt.

    Inductors are not iron core though. We don't use those things for anything except when big values are needed like 6.5 mH to 12.5 mH.

    In small values like you need I wouldn't consider them at all, unless I needed fishing weights.

    All our inductors are Alpha Core foil.

    Despite what some may think. They are easy to work with. No varnish or lacquer to scrape and clean either.

    They are also not expensive and average from just a dollar or two more than a wire wound to a dollar or two less.

    Sonically I feel their is no equal from side by side A/B test I have made using them and other types of inductors.

    We also de-wind to exact values for no additional charge.



    I guess I would be one to argue that one. What they carry is mid-fi, entree level, or budget components across the board. No best of anything to be found there.

    Steve, the only other company that I know of that has all of that in stock would be Sonic Craft.

    If you are looking to save a few bucks than try to get it all from one place and you'll save the bucks from less shipping charges.
     

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