Crossover Inductor Coils

Discussion in 'Audio Hardware' started by FrostEOne, Jul 27, 2018.

  1. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    Redesigned crossover, large inductors with the same orientation are just over 8" c-c, mid-range inductors are just over 4" c-c, closest inductor to tweeter inductor is over 5" c-c.
    I like this version a lot, probably best I can do while maintaining the 8" x 10" enclosure.
    This very well could be my production model. Comments and/or critique welcomed and appreciated.

    [​IMG]
     
    Last edited: Jul 30, 2018
  2. Davey

    Davey very clever with maracas

    Location:
    SF Bay Area, USA
    Progress report? All done? Amazing sound? Pictures? Maybe not a lot of interest here, but I'd definitely like to see how it turns out :)
     
  3. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    Lot of distractions delayed this project, but it's back on now.
    Came back to this post for the Goertz Inductors 12 AWG information you mentioned.
    Here's a shot of the preliminary layout of the components, shown with iron core coil in bass section.
    White mid-range board will be narrowed, leaving space on red bass board for up to 5" diameter air coil inductor.
    Black high range board will become blue when they come in, is out of stock currently.
    Crossover pictured measures 7" x 11", enclosure is 8" x 12"
    [​IMG]
     
    Last edited: May 15, 2019
    Davey likes this.
  4. Roger Beltmann

    Roger Beltmann Old...But not obsolete

    Location:
    helenville, wi.
    I've always purchased my wire in bulk on large spools. You buy it by the pound. You can wind your own inductors and save huge amounts of cash. You just need a LCR meter and some empty spools. I even used to make my own spools out of large wood dowels and plywood end caps. That way you can custom make any value or wire diameter choke you desire.
     
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  5. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    I find this interesting, but sounds like it'd take a lot of trial and error?
     
  6. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    Researched DIY choke coils, found enough information to give it a try.
    Air Core Inductor Calculator V 1.5 - Shavano Music Online - Air Core Inductor Calculator
    Thanks for the suggestion!
     
  7. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    Wow coil needed 5.000 mH - 0.41 Ohms would be larger than anticipated.

    5.6" Air core ID
    1.41" Height
    12ga wire, 156 turns, length 258.3' Long
     
  8. Roger Beltmann

    Roger Beltmann Old...But not obsolete

    Location:
    helenville, wi.
    There is an easy way to check inductance while winding. All you need is a LCR meter and a very sharp sewing needle. Clip one end of the meter to the stripped low side of the inductor you are winding. Clip the other meter lead to the sewing needle and use it to make a pin prick on the enamel of the wire on the winding side. This gives you an exact value of the inductance as winding progresses. This way you can wind two inductors with the exact same value. I don't worry about the microscopic pin prick in the enamel as its never posed a problem. I wind guitar pickups with a winding machine I built but audio inductors I wind by hand. You can make some pretty decent looking chokes if you're careful while winding. When you're finished winding the choke dip it in some shellac to freeze the coil and let it dry. If your chokes look a bit ratty just take some white vinyl tape and wrap the coils. They look just as good as the retail priced ones. If the pin prick is bothersome take a dab of finger nail polish,cover it and proceed winding. I've never done this but I already can hear the feedback. Some of the chokes in the Gemini crossover I scratch built specify very small wire diameter and oddball values. No problem !!
     
    Last edited: May 18, 2019
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  9. FrostEOne

    FrostEOne Likes it cold! Thread Starter

    Location:
    Iowa, USA
    Thanks for the tips, this is a first time adventure.
    Going to check local electric motor shop Mon., know the owner, they'd have proper wire, shellac etc.
     
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  10. head_unit

    head_unit Forum Resident

    Location:
    Los Angeles CA USA
    Iron core is not necessarily bad, if the current is well below saturation.
     
  11. Roger Beltmann

    Roger Beltmann Old...But not obsolete

    Location:
    helenville, wi.
    Thanks for the interest. Wind a couple of small chokes first (.1-.2mh) until you get the hang of it. I believe the largest I've wound is about 6 to 8 mh and 16 to 18 gauge wire. Best of luck.
     
  12. head_unit

    head_unit Forum Resident

    Location:
    Los Angeles CA USA
    I remember hand winding coils my first time-satisfying, but mostly I bought after that. Hard to get DCR down as much as paralleled iron ones! Or I forget what but there are some core materials more linear than iron. I'm kinda dimly remembering that air cores have more stray field or more influence on each other however that could be mistaken.
     

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