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  • DIY Inductors

    So... in keeping with my insufferable miserly behavior, I have decided that the prices being asked for coils is becoming offensive to me. My wife says I am a petty ba****d, but to each their own...

    I understand I need magnet wire - are their more and less desirable coatings?

    Bobbins - sources?

    How many feet of wire is there in, say, a typical 18awg, 0.20 mH air core coil? According the charts I found here, 18awg copper has about .00751 ohms/foot. If I look at this inductor, it has a DCR of 0.20 ohms which implies >25 feet of wire in a coil. Am I thinking correctly?

    Doing some preliminary shopping for magnet wire turns up prices ranging upwards from $10-20/pound. So it looks like I can save a little money given one source I found is offering 100 ft of 18awg magnet wire (1/2 pound) for ~12 dollars. This would appear to be enough wire to wind four 0.20 mH inductors, which would cost me ~15 or so.

    Personally, saving three dollars makes me happy - until I think of the time involved in counting hundreds of turns of wire around a little plastic bobbin.

    Which brings me to my next question. Erse and Jantzen and them must bathe their air cores in something - what might it be? We have some UV activated conformal coating at work, is it something like that? We use it because it has an extremely high dielectric strength... Is that one of the reasons (other than to hold it all together) that the big boys give their coils a bath?

    I guess what I am wondering is, if a guy can spend dozens of hours in the garage building speakers or a guy can spend all winter tying flies to go fishing, is the time spent winding worth the few bucks I save?
    Don't listen to me - I have not sold any $150,000 speakers.

  • #2
    Re: DIY Inductors

    If the act of making them is appealing to you, than its worth it. If you are doing it just to save money, than I would say not even close to being worth it.
    My projects
    https://picasaweb.google.com/112307725038877176664

    Comment


    • #3
      Re: DIY Inductors

      I'm one of the few who has wound my own inductors, both air core and ferrite core. It's a lot of work.


      Originally posted by johnnyrichards View Post
      So... in keeping with my insufferable miserly behavior, I have decided that the prices being asked for coils is becoming offensive to me. My wife says I am a petty ba****d, but to each their own...

      I understand I need magnet wire - are their more and less desirable coatings?

      Bobbins - sources?

      How many feet of wire is there in, say, a typical 18awg, 0.20 mH air core coil? According the charts I found here, 18awg copper has about .00751 ohms/foot. If I look at this inductor, it has a DCR of 0.20 ohms which implies >25 feet of wire in a coil. Am I thinking correctly?

      Doing some preliminary shopping for magnet wire turns up prices ranging upwards from $10-20/pound. So it looks like I can save a little money given one source I found is offering 100 ft of 18awg magnet wire (1/2 pound) for ~12 dollars. This would appear to be enough wire to wind four 0.20 mH inductors, which would cost me ~15 or so.

      Personally, saving three dollars makes me happy - until I think of the time involved in counting hundreds of turns of wire around a little plastic bobbin.

      Which brings me to my next question. Erse and Jantzen and them must bathe their air cores in something - what might it be? We have some UV activated conformal coating at work, is it something like that? We use it because it has an extremely high dielectric strength... Is that one of the reasons (other than to hold it all together) that the big boys give their coils a bath?

      I guess what I am wondering is, if a guy can spend dozens of hours in the garage building speakers or a guy can spend all winter tying flies to go fishing, is the time spent winding worth the few bucks I save?

      Comment


      • #4
        Re: DIY Inductors

        Honestly, I found some green magnet wire that is the cats meow. I might take the plunge just to have green inductors
        Don't listen to me - I have not sold any $150,000 speakers.

        Comment


        • #5
          Re: DIY Inductors

          Originally posted by johnnyrichards View Post
          so... In Keeping With My Insufferable Miserly Behavior
          Lol!

          Comment


          • #6
            Re: DIY Inductors

            Anyone try these low cost inductor winding machines?

            http://cgi.ebay.com/Electric-Coil-Tr...ht_3172wt_1137

            http://cgi.ebay.com/Manual-Coil-Wind...7#ht_680wt_911

            Comment


            • #7
              Re: DIY Inductors

              I asked at the local electric motor repair shop a few weeks ago. They seemed willing to order me some wire. Have to get 10lbs reels at a time. Ballpark price quote was $90. Will vary by current price of copper, awg of wire, etc.

              Given the low market price of copper (14~15 cents a pound), it really is outrageous what something as simple as wire cost the end user.
              "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy." --Winston Churchill

              Comment


              • #8
                Re: DIY Inductors

                green inductors? i want some too:D
                " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                Quote Originally Posted by hongrn. Oct 2014
                Do you realize that being an American is like winning the biggest jackpot ever??

                http://www.midwestaudioclub.com/spot...owell-simpson/
                http://s413.photobucket.com/albums/pp216/arlis/

                Comment


                • #9
                  Re: DIY Inductors

                  Mmmmm..... green....

                  Comment


                  • #10
                    Re: DIY Inductors

                    Originally posted by robwest View Post
                    I asked at the local electric motor repair shop a few weeks ago. They seemed willing to order me some wire. Have to get 10lbs reels at a time. Ballpark price quote was $90. Will vary by current price of copper, awg of wire, etc.

                    Given the low market price of copper (14~15 cents a pound), it really is outrageous what something as simple as wire cost the end user.
                    Current spot price for copper is just under $3.00/lb

                    Comment


                    • #11
                      Re: DIY Inductors

                      Originally posted by ozob View Post
                      Mmmmm..... green....

                      THATS what I'm talking about.
                      Don't listen to me - I have not sold any $150,000 speakers.

                      Comment


                      • #12
                        Re: DIY Inductors

                        a 0.2mh inductor using 18awg wire uses about 29 feet of wire and has a resistance of 0.19 ohms.

                        costs around 1-2 dollars if you don't count your time.

                        Comment


                        • #13
                          Re: DIY Inductors

                          Well, ordered a $30 LCR meter and a pound of green 20awg magnet wire. I have something brewing in mind for a winder... If it works out, good on me. If it doesn't, Erse Audio is a click away.
                          Don't listen to me - I have not sold any $150,000 speakers.

                          Comment


                          • #14
                            Re: DIY Inductors

                            Heres a great link for you.
                            Shavano Inductor Calculator
                            If you need something small like .1mH you can wind it on a small spool to make them compact. With shipping and having to wait, I just wind my own. I've just gone to a place that rebuilds motors to buy copper wire.

                            Comment


                            • #15
                              Re: DIY Inductors

                              I use the following inductor calculator:

                              http://www.diyaudioandvideo.com/Calculator/Inductor/

                              Comment

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