Handy guide to the "proper" juxtaposition of inductors in crossovers

Saw this uploaded to Flikr & thought it was a simple and handy guide for anyone who's wondering about how to arrange inductors in a circuit to minimize any deleterious cross-coupling between inductors. :)

7iyiem22gs1o.png

source: https://flic.kr/p/Mo3DfH
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Comments

  • F1nutF1nut Posts: 40,613
    Good post Mark. I saw someone's crossover upgrade recently that could have used that info.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • gmcmangmcman Posts: 1,267
    @mhardy6647 Thanks for sharing that.

    So does this put the setup for some of our inductors in the "very bad" category? Or does the plastic framework reduce this cross-coupling?

    Web pic of 2.3TL factory inductor layout.

    t6lw51336eig.jpg
  • mhardy6647mhardy6647 Posts: 19,542
    Any normal plastic should be invisibile to the electromagnetic fields around the inductors. Those two are at right angles, which is good -- their physical proximity is less good, but we're still not lookin' at a worst case scenario -- so all is probably fine.

  • delkaldelkal Posts: 345
    mhardy6647 wrote: »
    Any normal plastic should be invisibile to the electromagnetic fields around the inductors. Those two are at right angles, which is good -- their physical proximity is less good, but we're still not lookin' at a worst case scenario -- so all is probably fine.

    Unless I am seeing it wrong it looks like number 4.............Very bad and worse case scenario
  • VR3VR3 Posts: 22,371
    That is proper placement, no worries

    That placement is not even on the chart and it is fine
    - Not Tom

    Vr3Mods.com ///// Version3Audio.com

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • gmcmangmcman Posts: 1,267
    VR3 wrote: »
    That placement is not even on the chart and it is fine

    Unless I'm seeing incorrectly...looks just like fig 4 when rotated 90 deg.
  • mhardy6647mhardy6647 Posts: 19,542
    edited September 18
    Some info from Pat McGinty (the "Meadolark" guy) on empirically testing for inductive coupling here:
    http://www.hifihaven.org/index.php?threads/a-little-pictorial-guide-on-the-juxtaposition-of-inductors-in-a-crossover-for-diy-or-refreshing.4024/#post-76833
    The problem with the juxtaposition shown in the photo a few posts back is the physical proximity of the coils. It's certainly not optimal, but it is probably, empirically, fine.
  • VR3VR3 Posts: 22,371
    My experience with measuring inductors says that it makes such a small difference that it won't matter
    - Not Tom

    Vr3Mods.com ///// Version3Audio.com

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • VR3VR3 Posts: 22,371
    I've found 2, 3 and 8 to be the worst
    - Not Tom

    Vr3Mods.com ///// Version3Audio.com

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • steveinazsteveinaz Posts: 18,414
    No, not like #4. His 2 are sitting on edge, neither is sitting flat.
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  • gmcmangmcman Posts: 1,267
    edited September 19
    For the record, I'm not doubting how well the crossovers work, and they do with the orientation in my pic..just comparing to the diagram.
    steveinaz wrote: »
    No, not like #4. His 2 are sitting on edge, neither is sitting flat.

    What if we take the pic and rotate 90 deg, then instead of looking at the top, imagine looking at the side...nearest the bottom of this pic.

    fvj7d8xodkpi.jpg
  • ZLTFULZLTFUL Posts: 4,672
    The point is, they are 90* orientation from each other which helps reduce the inductive interference.
    Greater distance = OK solution
    90* = better solution
    90* + greater distance = best solution
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • mhardy6647mhardy6647 Posts: 19,542
    ZLTFUL wrote: »
    The point is, they are 90* orientation from each other which helps reduce the inductive interference.
    Greater distance = OK solution
    90* = better solution
    90* + greater distance = best solution


    egg-zack-a-tack-ly.

    :|
  • gmcmangmcman Posts: 1,267
    ZLTFUL wrote: »
    The point is, they are 90* orientation from each other which helps reduce the inductive interference.
    Greater distance = OK solution
    90* = better solution
    90* + greater distance = best solution

    I agree.

    This is also 90 deg. I want to say that #4 is not referring to this, but the 1st pic.

    omv6xj0r78mw.jpg





    And again, just curious if either way will make a larger difference, especially in our crossovers.

    I'm not complaining....speakers sound great. B)
  • mhardy6647mhardy6647 Posts: 19,542
    as a truism -- a little more space between inductors is better if circumstances permit. I like to give my DIY XOs room to breathe :) In fact -- why put 'em in the box at all? No real value added (especially if one wishes to... umm... experiment.

  • verbverb Posts: 3,985
    Interesting lesson professor. I found this. Right hand rule. Explains why the orientation and 90 angles can be placed closer together.
    70thmlkv5471.png
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  • ken brydsonken brydson Posts: 7,231
    verb wrote: »
    Interesting lesson professor. I found this. Right hand rule. Explains why the orientation and 90 angles can be placed closer together.
    70thmlkv5471.png

    What is this about again?
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  • ZLTFULZLTFUL Posts: 4,672
    verb wrote: »
    Interesting lesson professor. I found this. Right hand rule. Explains why the orientation and 90 angles can be placed closer together.
    70thmlkv5471.png

    What is this about again?

    It's about the "flow" Ken!
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • delkaldelkal Posts: 345
    All of the inductor photos are the same as what is shown in figure 4. And if the table is correct it is the worse setup. It doesn't matter if the inductors are placed flat side by side, tilted side by side or even on top of each other on a board. The only thing that matters is the orientation of the copper windings. It is number 4.

    You can se it easier if you put your pointer finger on each hand thru the hole in each inductor. Your fingers will be pointing in a T. No other orientation in the table will do that.

    But is this table correct?

  • delkaldelkal Posts: 345
    VR3 wrote: »
    My experience with measuring inductors says that it makes such a small difference that it won't matter

    Do you take the measurement when BOTH inductors are hooked up, charged and have a current? Testing one inductor at a time won't show much of an effect. And if the neighboring inductor is not hooked up to anything it will have zero effect (no circuit for the coil to do anything). But when both inductors are charged and acting like a magnet thats when you will have a big effect.

  • Viking64Viking64 Posts: 3,604
    I just want to eat doughnuts.
  • delkaldelkal Posts: 345
    Viking64 wrote: »
    I just want to eat doughnuts.

    Put a doughnut on each pointer finger, look at the chart, play around a little, then eat them!

    If you still don't see it get the next two doughnuts...............
  • Viking64Viking64 Posts: 3,604
    delkal wrote: »
    Put a doughnut on each pointer finger, look at the chart, play around a little, then eat them!

    If you still don't see it get the next two doughnuts...............

    Or maybe an electrolytic cannoli?
  • F1nutF1nut Posts: 40,613
    gmcman wrote: »
    ZLTFUL wrote: »
    The point is, they are 90* orientation from each other which helps reduce the inductive interference.
    Greater distance = OK solution
    90* = better solution
    90* + greater distance = best solution

    I agree.

    This is also 90 deg. I want to say that #4 is not referring to this, but the 1st pic.

    omv6xj0r78mw.jpg





    And again, just curious if either way will make a larger difference, especially in our crossovers.

    I'm not complaining....speakers sound great. B)

    That is the same as #4 because the coils are going in the same direction. That is, if you stood up the one laying down it would be parallel to the one on end. Now, if the one laying down was stood up on end and turned 90 degrees that would be good.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • F1nutF1nut Posts: 40,613
    edited September 19
    delkal wrote: »
    All of the inductor photos are the same as what is shown in figure 4. And if the table is correct it is the worse setup. It doesn't matter if the inductors are placed flat side by side, tilted side by side or even on top of each other on a board. The only thing that matters is the orientation of the copper windings. It is number 4.

    You can se it easier if you put your pointer finger on each hand thru the hole in each inductor. Your fingers will be pointing in a T. No other orientation in the table will do that.

    But is this table correct?

    In gmcman's photo the coils are in a "T" configuration, which is ok.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • agfrostagfrost Posts: 2,177
    gmcman's picture is "none of the above" when looking at the original diagrams. The SDA inductors are placed like this:

    l80uaf4hk3gg.png
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Marantz DV-9500 * Modded Adcom GDA-600 DAC * Rythmik F8
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  • delkaldelkal Posts: 345
    Lets just say this is not a handy guide. It is either wrong with number 4 being very bad or that a lot of people can't understand the difference between number 4 and number 6.
  • Viking64Viking64 Posts: 3,604
    I've been up all night testing these various examples and I still haven't been able to sew the ripped 3/4 sleeve of my Captain and Tennille baseball shirt. :'(

    7hz6ozbgni7x.jpg
  • agfrostagfrost Posts: 2,177
    delkal wrote: »
    Lets just say this is not a handy guide. It is either wrong with number 4 being very bad or that a lot of people can't understand the difference between number 4 and number 6.

    Care to illuminate us as to who comprises "a lot of people?"
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Marantz DV-9500 * Modded Adcom GDA-600 DAC * Rythmik F8
    Micro Seiki DQ-50 * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
  • agfrostagfrost Posts: 2,177
    ...I'll follow up my previous diagram with this one, which I posit is the same as number 4 (and different from the first one I posted). In essence an "L" instead of a "T".

    zarlyv20qsqg.png


    Not an electrical engineer nor a crossover designer, so I can't wax poetic as to why/how these are different, but my visual-spatial skills tell me there's a difference.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Marantz DV-9500 * Modded Adcom GDA-600 DAC * Rythmik F8
    Micro Seiki DQ-50 * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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