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Building a Magnetic PUP, Any help on design????

Brand new to this ball of wax after my wife got me a ukulele and I decided to build a DIY amp (runoffgroove little gem). It didn't work well with the uke but did with my old Peavy guitar so I started looking into different ways to fix the impedance mismatch and then suddenly I'm building a canjo for my youngest daughter....

I digress but anyways I want to build a magnetic pickup out of a wall wart and have found a nice 12 volt model. I watched the video from the fella who started building these and have some questions about pickup design. I've scraped as much as I can from google but still have questions. Namely....

1. If you build a pup with a magnet under neath the coil and then put poles on top does it matter which way the magnet is polarized? I.e. can it be polarized horizontally? I think it can if I remember my electromanetics 101 but cant remember hot to visualize which way creates the most inductance/power.

2. If you use poles on top of that magnet rather than placing it inside the coils do the poles have to be in contact with the magnet? I think the answer is no because it's the field that is being impacted by the poles so there is no need to be touching the magnet.

3. What does the distance between the coils and the poles and/or magnet do to the performance of the pickup? Specifically, does a single really thick bar type pole that goes across all of the strings need to be close to the wall-wart coil or can there be quite a bit of white space in there without hurting performance too much?

I know many of these are noob questions and I should be able to get out my old books and pencil out some of the key bits but I'd like to seek the voice of experience first. Many thanks....

Billy

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Permalink Reply by Jimbo Cawthron on June 5, 2012 at 6:24pm

Oh yes I did A lot more power was coming Through the pups when I added those I have a video on youtube so you can hear them , That is the pups just on a marsell practice app that you hear in the vid. here is the link...

JIMBOS PUPS

I tried what you are doing and it was just a lot easier for me to wind my own.
I hope you have fun with your project, after all that is what the cbg is all about is just to have fun playing around with what you are comfy with.

GOOD luck brother!

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Permalink Reply by Skeesix on June 6, 2012 at 6:23am

Try this - don't take the blades out. Attach a magnet to the bottom of the blades. I'm thinking something stronger like a neodymium might be best. The blades should act as a pole piece. Hook up either just one of the coils, or both coils in series.

If you really want to take it apart, putting the transformer in a vice while you work on it should make it safer.