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Magnets & Copper Wire: A Pickup Building Thread

#921
slowburnaz said:
According to https://music-electronics-forum.com...up-makers/13927-peavey-t-40-bass-pickup-specs, it seems those coils have 3750 turns of 42awg on them.
Click to expand...
OK. As we can only assume that's accurate, something later in the thread makes me wonder.
"My Toasters average 2.8k per coil. My Blades average 5.3k per coil."

"The 3750 winds of 42 awg sounds about right for 2.8k."

I was of the understanding they were basically the same pickup, Toasters vs Blades, but double the DCR seems well off. I understand the magnets may well be different but that seems like a big difference.
 
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#922
#923
A9X said:
OK. As we can only assume that's accurate, something later in the thread makes me wonder.
"My Toasters average 2.8k per coil. My Blades average 5.3k per coil."

"The 3750 winds of 42 awg sounds about right for 2.8k."

I was of the understanding they were basically the same pickup, Toasters vs Blades, but double the DCR seems well off. I understand the magnets may well be different but that seems like a big difference.
Click to expand...

Yeah... if 5.3k is the true reading for one coil, I'd make a Wild Ass Guess of around 6250 turns.
 
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#924
A9X said:
OK. As we can only assume that's accurate, something later in the thread makes me wonder.
"My Toasters average 2.8k per coil. My Blades average 5.3k per coil."

"The 3750 winds of 42 awg sounds about right for 2.8k."

I was of the understanding they were basically the same pickup, Toasters vs Blades, but double the DCR seems well off. I understand the magnets may well be different but that seems like a big difference.
Click to expand...

Yeah, that seems like a lot to me, too.

slowburnaz said:
Yeah... if 5.3k is the true reading for one coil, I'd make a Wild Ass Guess of around 6250 turns.
Click to expand...

That’s a good guess, but we’re working under the assumption that those readings are accurate. There isn’t really any way to know for sure until I have a functioning T40 pickup for comparison.
 
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#925
Freekmagnet said:
I just got this non-functioning T-40 Super Ferrite pickup for $30. I've been wanting to replicate this pickup since I got started winding pickups, so I'm hoping this will get me going. I imagine that at some point, I'll have to find a functioning version pickup to test against my own pickup. However, T-40 stuff is getting pretty pricey. Apparently the Peavey Forum basses also had Super Ferrites in them, and those are still fairly inexpensive. My nephew has a Forum - haha, maybe I could borrow his bass!
Click to expand...

Cool project!

Yes, Forums, Patriots, Dyna Bass, TLs etc. used "Super Ferrite" pickups. However, as far as I know, all those used the single coil version of the Super Ferrite, whereas the T-40 was a humbucker. They can't be too similar since the magnet ran between the two blades on the humbucker and I assume there is only one blade on the single coil design. Maybe dual magnets (one on each side of the blade)?

I am not going to disassemble the pickup on my Patriot, but I could make some measurements with a gauss meter to try to determine the magnetic field shape if that would help.
 
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#926
Jeff Siddall said:
Cool project!

Yes, Forums, Patriots, Dyna Bass, TLs etc. used "Super Ferrite" pickups. However, as far as I know, all those used the single coil version of the Super Ferrite, whereas the T-40 was a humbucker. They can't be too similar since the magnet ran between the two blades on the humbucker and I assume there is only one blade on the single coil design. Maybe dual magnets (one on each side of the blade)?

I am not going to disassemble the pickup on my Patriot, but I could make some measurements with a gauss meter to try to determine the magnetic field shape if that would help.
Click to expand...

Wow, thanks for the offer! I have the magnetic structure, so the big piece of the puzzle would be the turn count. If I had a DCR that I was 100% certain about, I could kinda estimate the turn count.

Yeah, I played that Peavey Forum my nephew has. I actually found it at a local music store a couple years ago. It's a great playing, great sounding bass and they only wanted $300 for it. I called my nephew and he came down and snagged it. I should have bought it, but now that I'm a luthier, I'm more reluctant than ever to buy an instrument I don't need. They start to pile up pretty quick.
 
#929
BTL said:
Lindy Fralin builds two 5-string pickups for me under a P90 cover with no holes. The first is his Big Single, a sidewinder design that uses a magnet in top of a mild steel blade. The magnet used in the pickup is a bit of a trade secret and it's not what is shown in the photo.

In order to accommodate a 5-string bass, I had to have wider blades cut from mild steel. I also need to cut and glue together guitar bobbins. I made up a cutting jig and use a blade wrapped in packing tape as a gluing jig. These are ready for winding and Lindy's shop will take it from here.

View attachment 4371570

View attachment 4371571
Click to expand...
Well, this was a bust. The bobbins I glued together were too bumpy for Fralin to use, so I'm back at square one. Does anyone have a vendor that can mill or 3D print bobbins from a .dxf file?
 
#934
BTL said:
Awesome! I've registered with xometry and I'm just waiting for an updated .dxf file.
Click to expand...

Sweet! I can give you a discount code if you want, too. Might save you some cash... though I'm not sure what the minimum for that is.

EDIT: Looks like it's $50 off any order of $300 or more.
 
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#935
@slowburnaz Once I have pricing, I will check back with you on that...thanks!

On a related note, I did a little digging around on fabricating a nickel-silver dogear P90 baseplate for this project, but came up blank on a cost-effective, short-run stamping option. As an alternative, I plan to use Send Cut Send to laser cut the plate in 0.040 brass, make the bends manually with seaming pliers, then solder brass nuts to the ears as I have been doing with the current baseplates.
 
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#937
I had a couple custom dies made, so now I can make really accurate cutouts of stuff like wire mesh for the pickups I do with exposed poles:

IMG_20220103_125649_842.jpg


This stuff is fun!
 
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#938
slowburnaz said:
I had a couple custom dies made, so now I can make really accurate cutouts of stuff like wire mesh for the pickups I do with exposed poles:

View attachment 4532403

This stuff is fun!
Click to expand...

I'd like to see those punching dies! How are they made? Who made them for you? How much did they cost? Do you do the punching yourself in an arbor press, or what?
 
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#940
Bruce Johnson said:
I'd like to see those punching dies! How are they made? Who made them for you? How much did they cost? Do you do the punching yourself in an arbor press, or what?
Click to expand...

They're actually "steel-rule" dies... the kind used for cutting paper, foam, plastic, etc. Essentially anything that you can cut with scissors. Works great for this wire mesh stuff.

The dies look like so:
20220107_082008.jpg
20220107_082019.jpg
20220107_082105.jpg


They're used in a sort of roller machine that my wife had for doing some of her stuff.

The folks I had make mine are called Custom Shape Pros.
 
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