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Charlie Christian Pickup

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4/30/2006 4:11 PM

Charlie Christian Pickup

In the latest issue of a M.I. trade rag, "The Music & Sound Retailer" there is a full-page article on the Charlie Christian pickup, written by jazz guitarist Kenny Gill. Kenny just raves about the C.C. pickup and says that he's tried all sorts of pickups and nothing compares, in his view. He says, "Its tone is well balanced, it has a velvety smooth response, and it has that great jazz sound that I've never been able to get from another pickup." That's just a portion of his praises of the C.C. pickup. What caught my attention was that this pickup uses Cobalt 59 magnets.

Have any of the builders here used Cobalt magnets? If so, what is unique about the magnetic properties of Cobalt magnets, versus ceramic or AlNiCo. Does Cobalt 59 also have a mix of other metals like Aluminum or Nickel?

4/30/2006 7:04 PM

I don't really think its the magnets that account for most of that pickup's tone. I've done an awful lot of work on blade pickups and actually working on a newer version of my Little Charley pickup as we speak to get closer to the real deal tone. Most of the tone comes from the steel blade. The reason is the eddy current factor, the big chunk of steel can sound angelic when you play lightly but dig into the strings and you create opposing eddy currents the more you beat on the strings which compressed the signal and helps give that horn honking tone. I have 3 different blade pickups, two use ceramic magnets (a hush falls over the crowd....) and you'd be hard pressed to hear much of a difference in magnet useage. The tone of the CC pickup comes from the fact that the blade in it is LONG and is wound with 38 gauge wire to help cut through the big size of the metal. Wire use in blade pickups is pretty critical, I've tried everything from 40 gauge heavy insulation wire to 44 gauge and they all have vastly differnt effects, but the esential tone of the pickup doesn't change that much. Use too much wire and the bass end turns to mud real fast. Inductance readings on blade pickups sometimes give opposite results to regular single coil pickups, backwards readings. Inductance can read real low with more wire and get higher as you unwind the wire, opposite of what you would think. I'm getting real damn close to what Charley Christian's tone on his records are in what I'm doing now. I'm working on this because some jazz guys want a thicker tone out of that pickup I make and the current model is brighter than the real deal though with appropriate use of bass and tone controls on amp and guitar you can get some wonderful jazz sounds out of the thing; they are a bitch to make but worth the pay off in playing tone for me......

5/1/2006 12:44 AM
Lukas	I think that 59Co magnet contains only cobalt, 59Cobalt is non radioactive isotop

5/1/2006 2:52 AM
Spence	Cobalt 59 is an isotope of Cobalt. So far, so good. If anyone offers you a Cobalt isotope make sure it's not Cobalt 60 or Cobalt 57 as you'll be irradiating yourself while you wind. The half life of Cobalt 59 is less than 80 days. As Cobalt is often alloyed with Samarium.

5/1/2006 2:41 PM

Dr. Strangelove

I heard they used CuNiFe, an alloy of copper, nickel, and iron. It could just as easily be a cobalt steel magnet.

There are a few alloys that don't fit the AlNiCo or ceramic ferrite recipe and which are mentioned in the Standard Specifications for Permanent Magnetic Materials (MMPA-0100-00).

I've pasted the appendix A table (115k in length) here:
<http://www.salvarsan.org/images/OddPermanentMagnetics.jpg> .

The MMPA-0100-00 document is a 28 page reference, about 1.44Meg and is available here:
<http://www.salvarsan.org/download/0100-00.pdf>

-drh
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5/2/2006 1:47 AM
Spence	Not forgetting CuNiCo..... And the Fender humbuckers were CuNiFe because it could be machined where AlNiCo couldn't.

5/2/2006 1:07 PM

I have a Rickenbacker 230 model electric which uses Samarium cobalt magents in its humbuckers, and RIC still uses that in their current humbuckers. They make for a powerful pickup but it often has too much highs and the sound can be somewhat harsh, at least in this design. I'd guess that you might get some of the same effect usin alnico 8 or something along those lines. Using samarium cobalt in a blade style pickup/charlie christian style pickup might be ok because of all that metal in there to dull down the highs, but who knows.

Greg

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