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Magnets & Copper Wire: A Pickup Building Thread

#901
MPU said:
Another multicoil under work to match the one I have on my Sterling Stingray. I’m making it a Walray with dual Lusithand NFP Special preamps. I wax potted the coils and made keeper bars this morrning. At the moment the coils are superglued to the base plate, wiring will be done later today when mrs is having her yoga lesson.

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I'm interested to hear what you think of the Lusithand special preamp. I've got a couple different versions of them, but don't have the very latest version where he smoothed out the filter roll off, so there's more of the upper midrange available in the first bit of knob twist.

For me, the sweet spot on that pre is with boost engaged and the filter rolled off just slightly. Lots of bark.
 
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#902
Just wanted to share a pic that shows the silver/chrome insert as well as the black ;-)...

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#905
slowburnaz said:
I've got some brass and stainless steel mesh I've used on some others.

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Oh yeah! I really like the design of your covers, because you could put all kinds of different materials in there, for different visual characters. From Heavy Metal to Old Timey. Different looks for different formulas of the internals. But they would all be distinctive of your brand. Clever product design.

All kinds of possibilities: Fabric, suede leather, synthetic pearl, etc.
 
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#909
slowburnaz said:
I'm interested to hear what you think of the Lusithand special preamp. I've got a couple different versions of them, but don't have the very latest version where he smoothed out the filter roll off, so there's more of the upper midrange available in the first bit of knob twist.

For me, the sweet spot on that pre is with boost engaged and the filter rolled off just slightly. Lots of bark.
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For me the sweet spot is pretty much the same but without boost. At least with MM pickup position. We'll see if that changes with dual pickups in Wal position. So far I like the Lusithand pre a lot.
 
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#911
Freekmagnet said:
Here’s a question for you guys: I just bought a non-functioning vintage pickup that I want to reverse engineer. However, it’s been gooped. I knew it would be, so it didn’t come as a surprise. Any tips on removing old epoxy from the coils?
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Ugh. I don't really know any way of removing the epoxy without destroying the wire and bobbins. I'm not aware of any solvent that would dissolve it. And epoxy has a higher melting temperature than most other plastics. You could take it outdoors to a fire-safe area and blast it with a propane torch. Save the metal parts from the smoking lump. But you'd wipe out the parts that you want to look at.

Epoxy is forever. Embed your diamonds in it. And your pickups, for permanence.
 
#912
Care to share a photo? What other materials are involved?

Is it cast into a solid block of epoxy like EMGs or Bartolinis? Some epoxy potted pickups can be kinda-disassembled by gently heating until the epoxy is soft (but definitely not melted) and then cutting/peeling it away. Suspending the pickup in a pot of boiling water works ok - it'll get to a state where it's like rubber and you can work with it then. I've disassembled a few epoxy potted pickups like this. I don't think you'll ever be able to unwind the coil but you can at least get the block of potting out of the way so you can see what's going on inside it in terms of overall structure.
 
#913
OK. So my disclaimer is that this should not to be considered a "project" yet, but here it is.

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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!

I'm both impressed and aghast with the engineering of this pickup. It's really easy to assemble and disassemble and that's very cool. But gooping the coils and the flexible leads was an unbelievably bad decision. It also looks like they melted part of the plastic bobbins while accessing the lead wires with a soldering iron. Sloppy sloppy sloppy.

It would be kind of neat to develop a direct T-40 replacement, but I'd have to do so with some concessions. I'd probably do my usual thing with cast resin encapsulation with a metal face shield and a PCB baseplate with right angle header pins to join the wires. Making that chrome metal cover would be too expensive. Chroming the steel poles would also be a prohibitive expense. The plastic tray that the assembly fits into is great and makes the pickup easy to build, but it adds maybe 5/16" to overall depth of the piece. The pickup is already freakin' huge as it is - I don't think it needs to be any deeper.
 
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#914
Freekmagnet said:
I've been wanting to replicate this pickup since I got started winding pickups, so I'm hoping this will get me started.
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Awesome. I've been interested in the innards of a T40 for a while and the potential for replication as they're getting expensive and I have a couple of basses I'd like to try one in. I'll be watching with interest.
 
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#915
A9X said:
Awesome. I've been interested in the innards of a T40 for a while and the potential for replication as they're getting expensive and I have a couple of basses I'd like to try one in. I'll be watching with interest.
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Yeah, I probably won’t get to this right away, but it would be cool if there was a functional alternative out there.

The Super Ferrite is a pretty straightforward pickup, but I don’t have all the specs. Big ceramic magnet, looks like a fairly medium wind count. Probably 42AWG wire. There’s a wind count/DCR reading floating around the internet that supposedly came from Chip Todd himself, but until I get this pickup apart, I have no way of confirming that info.
 
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#916
I'd be tempted to chop the coil right in half if it's non functioning, then measure the cross section of the wire wraps to get yourself a goal to start with. Assuming you can determine the wire gauge. In the last photo, the wire on the bobbin to the left looks really heavy to me, but that might just be a trick of the photograph. If I had to guess I would have said 40 or even 38.
 
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#918
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.

Seems a bit low, but I assume that the coils are wired in series with a tap between them for the crazy electronics setup.
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Those are the same specs I have. I probably got them from that exact same source.

With a big enough magnet, 3750 doesn’t seem out of line. The ceramic magnet on this pickup probably packs enough juice to get the party started.


dwizum said:
I'd be tempted to chop the coil right in half if it's non functioning, then measure the cross section of the wire wraps to get yourself a goal to start with. Assuming you can determine the wire gauge. In the last photo, the wire on the bobbin to the left looks really heavy to me, but that might just be a trick of the photograph. If I had to guess I would have said 40 or even 38.
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Haha yeah, the nuclear option could work. I want to avoid that if I can.

I thought those wires looked thick too, but I can’t picture Peavey going the extra mile and designing a low-impedance pickup for the T40.
 
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#919
That magnet is stupid big. What are the dimensions? I have some ceramic bars that are .25" x .5" x 2.5" and they're borderline overpowering with anything more than 5,000 turns in a steel blade humbucker like that. If those magnets are as big as they look then I'd believe the low turn count.
 
#920
dwizum said:
That magnet is stupid big. What are the dimensions? I have some ceramic bars that are .25" x .5" x 2.5" and they're borderline overpowering with anything more than 5,000 turns in a steel blade humbucker like that. If those magnets are as big as they look then I'd believe the low turn count.
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I don’t have it in front of me right now, but I’m guessing it’s .25” x .75” x 2.5”.
 
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