Originally posted by MisterBzr
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The position of this low Z pickup should behave just like other high Z pickups relative to the string position relative to the bridge. Try using some flat ceramic magnets and see what happens.
You are pretty much free to try any variety of magnets. I have used small ring magnets .25" dia with a .125" center hole neo type. I use a piece of rubber or weather stripping under the magnets then use a screw in the center to make an adjustable pole piece. If you have an acoustic guitar you can use craft sticks (like icecream pop sticks). They come in .275" wide and .687" wide. They allow you to make the pickup on the craft stick and then bend down the wire under the stick to mount the current transformer and finally easily mount it to an acoustic guitar. You will get a nice more acoustic-like quality as the higher frequencies are picked up that are not normally heard in a high Z pickup. The challenge here is to obtain a nice string balance as the B-string tends to dominate the sound because it is one of the thicker solid cores. I normally make a string loop with about a .25" dip under the B string then I bend down the wire feed about .375" wide centered under the B string to mount the current transformer. This helps reduce the output level of the B string. Magnet size and shape mostly define the options you can use in the string sensing loop shape.
Since you are not winding many turns for fine wire, the design of the pickup is mostly a mechanical issue to fit the constraints of the space you have to work with.
Read my thread "Moving coil pickups for the technically curious" to see how to use moving metal strings in a magnetic field as the actual pickup by using some 8 ohm to 20K ohm transformers.
You will start learning about another side of pickup design here with these current-driven pickups.
Joseph Rogowski
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