Silent single coil

[Possum]

So on this offset poles idea you have ferrite poles topped with steel slugs, I'm not quite understanding what you did there. I think you're probably getting pretty low guass at the poles which is probably why they are less bright than just alnico alone. cool idea...

[Mike Sulzer]

Originally Posted by Possum

So on this offset poles idea you have ferrite poles topped with steel slugs, I'm not quite understanding what you did there. I think you're probably getting pretty low guass at the poles which is probably why they are less bright than just alnico alone. cool idea...

No, this is ferrite poles topped with small neo magnets. I use magnets somewhat smaller than jbf uses, and the field strength is between a humbucker and an alnico single coil. (This is my six coil pickups where the field direction alternates from pole to pole.)

I use a material with a pretty high permeability; I do not know what jbf is using. The permeability should affect the field strength, but I have not made measurements with different types of ferrite.

[jbforrer]

Hi Possum/Mike,

I'm much indebted to Mike for the details on the ferrite cores. I think it works well.

This is just a hobby to me, I'm not in the pickup-making business.

Attached is a picture of the parts of the pickup I made. The base material is from an old CD cover ... easy to score, snap, and file down. The ferrites cores are #73, like Mike described. The neo's are 3/16" by 1/16" (not 3/16 as said earlier)" #42 grade.

Here is is a test recording I made with the neck pickup. If you can detect any hum on the recording, it comes from my audio chain, not from the pickup.
http://www.johanforrer.net/Guitars/E..._recording.mp3

Thanks.

JB.

[Old Tele man]

Originally Posted by jbforrer

Here is is a test recording I made with the neck pickup. http://www.johanforrer.net/Guitars/E..._recording.mp3

...got a 'clean' clip without all the reverb and echo? I'd really like to hear what just the pickup alone can do.

...small (tiny?) pole pieces should be VERY harmonic sensitive, that is, not smeared nor "averaging" of the string vibrations, as occurs with larger diameter pole pieces.

...I'm guessing almost "hollow-body" like tonality...but also "picky" against large lateral (string bending) movements.

[Mike Sulzer]

Originally Posted by Old Tele man

...small (tiny?) pole pieces

The magnets on top are 3/16" in diameter. The ferrite pole pieces below are about .2" diameter if they are the same ones I use. Were you looking at those nails that I think might have been used for alignment?

If anyone is wondering, the ferrite is not a permanent magnet; it has high permeability, that is, it responds to magnetic fields by becoming magnetized while the field is applied, but the magnetization disappears when the field is removed. This is similar to steel, but the permeability is higher. This ferrite material is somewhat conductive, much less so than steel. Thus the coils tend to come out higher in Q than with steel or alnico. Thus, it might be necessary to load the pickup with a smaller resistor to get a particular sound. One can use a lower value of vol pot, or just add a resistor in parallel with the pickup. The resonant frequency might also be a bit high with these slender coils. It can be lowered with some parallel capacitance if necessary.

[Old Tele man]

Originally Posted by Mike Sulzer

Were you looking at those nails that I think might have been used for alignment?

...guilty! I thought those 'alignment/assembly nails' were the actual pole pieces that would be positioned under the strings...duh!

[jbforrer]

You have good ears Old Tele man. I left you a PM to try out a loaner in your own environment and take your time to explore it.

Thanks Mike for clarifying the bit about the magnets. Attached is a picture of the ferrite/magnet assembly next to a 0.710" long, 0.185" dia, Alnico magnet.

Regards.

JB.