Need help with multicoil design

[iunnox]

Hi, I'm a little new to this forum and pickup winding, and I have a somewhat ambitious design in mind for my first project. I want to make a EMG35 sized pickup that sounds mainly like a P, with a bit of Wal low end and Rickenbacker top thrown in.

Here's my idea so far:

4 Staggered 20mm bobbins (same height or slightly taller than P bass coils)
About 2.5K per coil of 43 or 42AWG
.195x531" or .250x.6" A5 rods, one per pole
Possibly a metal baseplate to increase inductance/ improve magnetic field

Does this sound like it will give me what I'm looking for?

[big_teee]

Welcome to the Forum!
I make some Multi-Coils in soapbars, P-bass, and Music Man covers.
Not much info out there on them.
It being a newer pickup design, You may not get many to share much!
Here are a few pics, loose, and in the test bass.
T

[iunnox]

Thanks, big_teee! I was actually just reading the unusual pickup thread on talkbass before I posted this. Your pickups look pretty cool, the sound clip of the staggered one sounded great!

My design is pretty similar to yours, except with shorter, fatter bobbins and smaller polepieces. It'll be interesting to hear the effect coil size has on different multicoils if I do go this route, most of the ones I've seen have pretty similarly shaped coils. I've heard that the main advantage besides have the coil closer to the pole is being able to use tall bobbins to get more clarity, so I'm hoping I don't end up with a "regular sounding" or unclear multicoil.

Would it make sense to use larger pole pieces since the P has 2 per string and I'm only using 1? I imagine the lost ferric/magnetic material would affect the inductance.

[big_teee]

I wouldn't use any smaller than .25" diameter sized rod magnets, because bass strings are larger,and vibrate further, than guitar strings do.
Also your magnet length you mentioned, is pretty short.
I like bright bass pickups, so I tend to go tall.
I don't know if you will gain anything with a metal base plate or not, that is more guitar ideology?
Give your ideas a try, All of my stuff is work in progress.
When I get a new idea, I try it.
Good Luck,
T

[iunnox]

They're actually a little larger than stock P bass rods (.187"), but the same height. I'm trying to get each coil as close to a P coil as I can, I figure that that's where most of that tone comes from.
I've read that any ferrous metal in your pickup will increase inductance, not sure if I'd need it, but P pickups are something like 10H.

I've got a bunch of ideas I'd love to try, but I'm broke right now. I'm trying to get as much info as I can to get the best result with the least amount of money.

Speaking of which, does anyone know of a good supplier for premagnetized A5 rods?

[big_teee]

Sounds like you know what you want.
I try to make pickups to sound better(to me), not like a vintage pickup.
If you want the P-Pickup tone, just build a split P pickup as is, like most guys do.
Also if you want that tone, why go to all the trouble to make Multi-coils?
Multi-coils don't sound like Vintage pickups, more Hi-Fi, but very efficient.
They are a PITA to make, very labor intensive, And if you don't like the way they sound, it is a usually a total redo, not just swap a part.
As far as magnets, wire, & parts, you might look at the resource thread, I have most of the vendors listed there.
http://music-electronics-forum.com/t30228/
Good Luck in your MC P-Bass 35 size Quest!
T

[iunnox]

There's a few reasons. One, it's going into my Cabronita P, which I'm turning into kind of a "modern" P. Two, I'm a big fan of multicoils and I want to impart that clarity and huge bottom end. Three, it's impossible to fit a P pickup into an EMG35 case, and I don't want to rout out my pickup cavity again.

What makes them harder to make? Other than matching the winds of each coil, it just seems like they'd take a little longer. I would imagine that it's easier to wind a round bobbin than a long single coil.

Either way, thanks for your insight! I'll post some sound clips here of whatever I end up making

[big_teee]

There's a few reasons. One, it's going into my Cabronita P, which I'm turning into kind of a "modern" P. Two, I'm a big fan of multicoils and I want to impart that clarity and huge bottom end. Three, it's impossible to fit a P pickup into an EMG35 case, and I don't want to rout out my pickup cavity again.

What makes them harder to make? Other than matching the winds of each coil, it just seems like they'd take a little longer. I would imagine that it's easier to wind a round bobbin than a long single coil.

Either way, thanks for your insight! I'll post some sound clips here of whatever I end up making

Sounds good and you have my support!
Multi-coils, there are just more of them, and you sit in front of the winder longer.
If you wind 10,000 turns on a bobbin, it doesn't matter if it is short or long.
The same sitting time regardless of length.
Don't forget to count the maching time for all the bobbin flatwork making, hole drilling and such.
That to me is some of the hardest part of the hand made pickup scene.
The sound clips sound great, keep us posted on your progress.
T