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  • low-z...ultra low...but if I....

    Here's my first post. Insults and jabs welcome.

    I rescused a couple of coils of wire from the company dumpster which were never intended for musical application; SquareD contactor coils. On a whim, I took some L-shaped peices of steel (mounting brackets) and some ceramic magnets I got cheap at Home Depot and taped it all together with scotch tape from my desk dispenser. (Can I make myself sound any more ameteur?) When I connected it to the input of my XTLive, I actually get a pretty good signal.

    To the point, my resultant ohms DC is about 16....not K. Should I be able to overcome the lack of windings with a stronger magnet and not use an impedance matching transformer?

  • #2
    Originally posted by scottmccullor View Post
    Here's my first post. Insults and jabs welcome.
    Allow me to be the first to insult you by welcoming you to the Pickup Makers Forum.
    I rescused a couple of coils of wire from the company dumpster which were never intended for musical application; SquareD contactor coils. On a whim, I took some L-shaped peices of steel (mounting brackets) and some ceramic magnets I got cheap at Home Depot and taped it all together with scotch tape from my desk dispenser. (Can I make myself sound any more ameteur?)
    For a fast proof of concept, it utterly rocks.
    "First, make it work. Next, make it good. Last, make it pretty."

    When I connected it to the input of my XTLive, I actually get a pretty good signal.


    To the point, my resultant ohms DC is about 16....not K. Should I be able to overcome the lack of windings with a stronger magnet and not use an impedance matching transformer?
    Not a hope. A stronger magnet will give more output (up to a point) while damping out string motion more.

    Grab a cheap impedance matching transformer from Radio Shack and try some more windings.

    -drh
    "Det var helt Texas" is written Nowegian meaning "that's totally Texas." When spoken, it means "that's crazy."

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    • #3
      so you've perfectly captured my design philosopy...except that I rarely get to the make it pretty. You should see pictures of my "Frankenpedal" box in which I mounted the Roland GR-7 and POD XTLive together. Ugly but effective.

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      • #4
        You should see the first winder I built. Works great, but my wife keeps thinking it's scrap for the fireplace! Well, okay that's where most of it came from, but it's not going back
        www.chevalierpickups.com

        Comment


        • #5
          Originally posted by scottmccullor View Post
          Here's my first post. Insults and jabs welcome.

          I rescused a couple of coils of wire from the company dumpster which were never intended for musical application; SquareD contactor coils. On a whim, I took some L-shaped peices of steel (mounting brackets) and some ceramic magnets I got cheap at Home Depot and taped it all together with scotch tape from my desk dispenser. (Can I make myself sound any more ameteur?) When I connected it to the input of my XTLive, I actually get a pretty good signal.

          To the point, my resultant ohms DC is about 16....not K. Should I be able to overcome the lack of windings with a stronger magnet and not use an impedance matching transformer?
          Search the thread where bbsailor went over his low impedance (one turn) pickup theory and experiments.

          Comment


          • #6
            well...mixed results

            So now I've cobbled together various pieces to make a test rig guitar. I would ask about the properties of oak as a tonewood, but in this case soft white plastic is what the pickups are mounted in.

            As predicted, the output is very low, but not so low as not to be usable. I've plugged into my Line 6 POD XTLive and just tweaked a few of my usual patches and I'm getting what I think is a pretty good result. It ends up sounding more like an acoustic but I'm not done tweaking yet.

            I'll attempt to upload these samples. Frankentar4.mp3 is a tube preamp emulation, totally flat and about 2 o'clock on the final gain and a compressor for a little more boost. I didn't normalize or process the samples at all other than what was done with the XTL.
            Attached Files

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            • #7
              And it get's uglier...but better?

              I installed an EMG preamp in an Altoids tin that an officemate had. The output is plenty useable although I've paid a price with hiss. It also helps when you select the right tab on the jack as ground and hot. It sound so much better when I'm not playing over a mexican radio station...literally.

              I also replace the ceramic magnets with some neodymium, lowered the bridge and mounted it more firmly. Yep, I know it's a tremolo bridge but I wanted it to be a hard tail.

              So does anybody have a clue what type of wire is found it a contactor coil? SquareD ain't talkin and I even work for a sister company.
              Attached Files

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              • #8
                if the grey thing in th middle is the magnet and the 2 pieces at the end are steel blades

                the magnet is installed wrong. it should have 1 pole facing to the strings and not have the N-S axis in parallel with the strings, at least in a conventional PU, which yours still seems to be.

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                • #9
                  it isn't

                  Not knowing how the polarity ceramic magnets that I used at first, I tried sticking it in the hole of that bobin, but it didn't really work.

                  The metal is so L shaped steel brackets that I glued to the inside of the bobin which also serve as mounting brackets. The gray thing in the middle is a piece of wood that I put there for extra support in case the glue didn't hold.

                  The magnets are actually on the bottom, attached to the metal brackets by their own force. You can see the ceramics I used at first in the earlier pictures as they were wider than the pickups. The neodymiums I'm using now fit the brackets exactly. I should post a pick of the back side.

                  I got to thinking this morning... Since these coils are made for contactors, I could safely run 120V through them without damage. Therefore, is there any reason I couldn't totally encase them in epoxy...or plastidip?

                  Comment


                  • #10
                    Originally posted by scottmccullor View Post
                    I got to thinking this morning... Since these coils are made for contactors, I could safely run 120V through them without damage. Therefore, is there any reason I couldn't totally encase them in epoxy...or plastidip?
                    I encapsulate my bass pickups in epoxy.
                    It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein


                    http://coneyislandguitars.com
                    www.soundcloud.com/davidravenmoon

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                    • #11
                      David, how much penetration into the coils does the epoxy get? Do you have any microphonics problems?

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                      • #12
                        I pot the coils first in either polyurethane or varnish.

                        But I think the epoxy would get pretty far into the coil judging by how much I have to put in... it sinks after a while and there's some bubbles, then I have to add more, and so on until it levels off.

                        Potting the coils in wax first would work fine also.
                        It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein


                        http://coneyislandguitars.com
                        www.soundcloud.com/davidravenmoon

                        Comment

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