Magnets & Copper Wire: A Pickup Building Thread

[Bruce Johnson]

I've also looked at using two sets of Mustang Bass pickups for that. They're only about 19 mm wide.

Yeah, those would probably work too. The main reason I'd go for the Quarter Pounders is the 1/4" dia magnets. The Mustang pickups have 3/16" magnets, right? To me, that would make the side-to-side aperture kind of narrow. But maybe not. You'd have to try it and see. How the string disrupts the magnetic field as it wiggles within it is probably the least understood area of pickup design.

 

[5tring]

Sure, that sounds like an interesting pickup arrangement, and a reasonable reason to go with single string pickups. Kind of a radical EQ curve, but it could sound nice. The biggest problem with multi-coils is the narrow width between strings. If you stagger them that dramatically, you may be able to use some standard coils. For example, four Duncan QP coils, turned sideways to put all the magnets in line with the strings. Wire them as two humbucking sets, and wire the two sets in parallel.

Thanks Bruce that’s a great idea

 

[Freekmagnet]

It's about twice the weight of the QP.

Sooooo...

...would that make your pickup a half-pounder?

 

[ctmullins]

Yeah, those would probably work too. The main reason I'd go for the Quarter Pounders is the 1/4" dia magnets. The Mustang pickups have 3/16" magnets, right? To me, that would make the side-to-side aperture kind of narrow. But maybe not. You'd have to try it and see. How the string disrupts the magnetic field as it wiggles within it is probably the least understood area of pickup design.

I had the same idea recently, but figured I could mount them slightly twisted, with one magnet on either side of the string, like Nordstrand has popularized. I assumed that mounting something like a QP coil with its magnet array parallel to the strings would result in a too-wide sensing aperture, perhaps dulling the high-frequency response. I’m stoked to learn that’s not the case!

 

[Teacher]

Multi-coil pickups:

I've done a fair amount of development of multi-coil pickups, but I went off in a different direction from what other pickup makers have done. I decided to make long, narrow, tall oval coils that are in line with the strings, like this:

View attachment 3233817

This is the quad-coil pickup that I used in my Series IV model Scroll Basses. Ignore for the moment the funny looking contraption around the bridge. That's the Mechanical Percussive pickup, which is a whole different animal. I'm going to start a separate thread talking just about them. Here, we're talking about the four black oval coils in the foreground.

The main reason I developed this quad-coil pickup is that I wanted to go with a 4" radius fingerboard on this bass. The 4" radius curvature is tight enough that it's really hard to get the pole pieces of even two coils to reach the strings. So, I decided to go with four separate pickup coils, which are individually adjustable in height. This way, I knew I'd be able to dial in the balance between the strings after it was built.

Here's the assembly of the four coils, mounted to a pair of aluminum bars. Each has a vertical travel of about 1/4".

View attachment 3233827

I also wanted this bass to be all passive, and not need any pre-amp to boost the signal levels. The string spacing is 3/4", which doesn't leave room for a round coil with very much wire on it. I wanted the pickups to have enough power and wire turns and resistance to operate on their own, all passive. So, I went with the idea of long oval coils, along the lines of the strings. The coils are each only 5/8" wide, but each contains three 1/4" dia x 3/4" tall Alnico 5 rod magnets. Plenty of magnetic power. The coils are tall and narrow, tight in around the magnets, 5000 turns of #41 wire. The coils end up at about 1.9K ohms each, 7.7K ohms total, wired in series.

I also made them as a full humbucking set. The coils are arranged alternating with the magnets North up and South up, and are wired going opposite directions through the coils. Plus, each coil has a full brass shielding shell around it. They are very quiet, noise-wise.

So, what do they sound like? Actually fairly close to a Seymour Duncan Quarter-Pounder P-bass coil set. A little more powerful. It's the same magnets, 12 instead of 8, all aligned right along the strings. The frequency curve is somewhat flatter than the Duncan QP. Because of the long sensing aperture along the length of the strings, this pickup is completely insensitive to harmonics. It picks them all up equally. When I had this pickup in the test mule, I found that I could move it forward and backward 2" with hardly any difference in sound.

The sensing aperture across the strings is narrower than a QP, because the magnets are directly beneath the string, rather than one on either side. But there are three in line. So, the magnetic field shape around the string is a long tunnel, rather than a wide span. Clarity and definition are a bit higher than the QP, but not a whole lot.

I was using the Duncan QP coils in my Series II and Series III model Scroll Basses, so I have some years of experience with them. The Quad pickup in the Series IV sounds fairly close to the QP coils. That's what I was aiming for, really. The advantage of the Quad is the ability to fit the 4" radius strings with adjustable levels. Plus it's a physically narrow pickup, fitting into the narrow space between the F-holes on the Scroll Bass body.

The downsides to the Quad pickup are cost and weight. It's four complete pickups, expensive to build. And more weight of magnets, wire and epoxy. It's about twice the weight of the QP. It's also kind of tall.

On the drawing board, I have an improved version of the Quad pickup. I'm planning to use it on one of my other upcoming model basses. Four 1/4" magnets per coil instead of three, more compact winding, better design of the bobbins and height adjusting screws. Pushing the idea a little further.

Here are some pictures of the Quad coils under construction:

Cast polyurethane half-bobbins, same process as I described above.

View attachment 3233830

Here's that tight, neat layered winding that I talked about. The opposite of scatter-winding. I make my coils dense and compact.

View attachment 3233831

The wound coil, with the wire ends carefully soldered to the terminals. I then cover them with soft glue.

View attachment 3233832

Potting the coils with CPES epoxy.

View attachment 3233840

The brass shielding shells, with their ground wires soldered to them.

View attachment 3233833

Preparing the shells and coils to go into the housing molds.

View attachment 3233834

Pouring in the black epoxy. West Systems 105/206 with black pigment.

View attachment 3233835

Out of the molds, gluing on the ebony caps.

View attachment 3233836

Final cleanup.

View attachment 3233837

These pictures are all from about 2008, ten years ago. I no longer make the Series IV model, or these particular pickups. But I still have all the tooling and molds. The current pickups I make go through a similar process. I've learned more and made improvements in the manufacturing steps and the pickup design. A lot of R & D work.

Crazy...I once pondered doing exactly this with Bill Lawrence narrow twin blades.

 

[Bruce Johnson]

Sooooo...

...would that make your pickup a half-pounder?

Yep, twice as many calories as you need.

Over on the Love Of Ampegs thread, you may have seen these, the Trussart SteelScrollPeg, a variant of my AMB-2 that I built working with James Trussart. All dressed up with metal plates, that later got engraved and etched. On two of them we initially went with twin Quad pickups, to be double-cool. That's 24 of the 1/4" magnets! But it ended up weighing over 12 lbs. Unworkable. So, I pulled them out and reworked those two basses with single AMB-2 pickups, got them down to 9 lbs.

 

[Bruce Johnson]

I had the same idea recently, but figured I could mount them slightly twisted, with one magnet on either side of the string, like Nordstrand has popularized. I assumed that mounting something like a QP coil with its magnet array parallel to the strings would result in a too-wide sensing aperture, perhaps dulling the high-frequency response. I’m stoked to learn that’s not the case!

Yes, the long oval coils definitely did not dull the high end. I wouldn't say that they boost it either. The main thing I noticed was that the harmonics are all nice and clear and even, at any fret position. Not spikey or very sensitive to pickup location. I also wondered whether the narrower aperture across the strings would cause any problems, but it doesn't seem to. If anything, it increases the definition and clarity. But not by a whole lot.

My understanding is that a single magnet directly under the string creates a nice almost hemispherical magnetic field shape around the string. Fairly compact and concentrated. Really good at detecting the fine movement of the string.

Now, Leo went with two smaller magnets on either side of the string. The magnetic field around the string is a more complicated shape, like a double lobe thing. More concentrated field strength out at the sides and a weaker area in the middle. Why did he do that? I've heard that the main reason was that he wanted to use the same 3/16" magnets as he was using in the guitar pickups, for economy. But the bass pickup needed more magnetic power, so he put in two per string. Or, it may be because the two magnet field makes the sound more thumpy and muddy, less clear and precise. That's what he wanted in his bass sound, at that time. And Fender stuck with that configuration for most of their bass pickups.

Notice that at MusicMan and G & L that changed; they went with single larger magnets directly under the strings. By that time, basses were becoming ping monsters. Clarity and high end became the thing.

So, yes, putting a row of magnets in a line under the string, and angling the line a bit, may be a blend between the two ideas. It could be interesting.

 

[Freekmagnet]

Sandwich sidewinder build, Part 2

Time for another post about my sandwich sidewinders. Before you read this, allow me to point out that the next few photos will illustrate my casting of the wound bobbins. These photos are from a previous iteration that used cylindrical neodymium magnets - I am now using ceramic bar magnets, but the process is exactly the same. I won’t be casting any bar magnet versions for a while, and I already have these pictures. To see the cardboard bar magnet version, please refer to this post:

Magnets & Copper Wire: A Pickup Building Thread

After I pot the pickups with CPES, I glue the terminals to the wound coils. I use those little header pins that you can buy at Fry's. They're super-cheap and they fit perfectly in the space. I suppose I could design a part and cast it myself, but these seem to work fine. I haven't tested them extensively in the field - I've only built a few of these and so far, I've only had them in one bass. Once I solder the wire to the terminals, I coat the joint with a nice blob of Titebond glue. I usually coat the wires with a thin coat as well. This is to keep the solder joint isolated and to protect the wires from thermal changes during the casting process.

Here's the picture - again, pretend this is one of my cardboard bobbins - not the Garolite ones pictured here*

*In case you were wondering, the reason I don't use Garolite for the ceramic bars is because cutting that slot in that material is difficult. I couldn't find anyone to laser-cut Garolite - apparently it doesn't cut with a laser very well either.

My mold making process is fairly crude. This basically involved making one cast using modeling clay as a filler. I used ball bearings as registration points. I use foamboard and hot glue as a container. I'm hoping to upgrade to Legos at some point so I can build my forms from little bricks instead

The master is cut from piece of 1/4" thick aluminum. I shaped it with a file and a sander.

Notice I backed one edge all the way to the side of the box. Leaving on side open, this is where I will actually pour the epoxy into the mold. The wire terminals will be sticking out of the back. Once I poured the Smooth-On OOMMOO 30 silicone casting compound and let it set, I got this:

From which I made the other half of the mold – I’m actually making a couple of different parts here…

Once I have the completed mold, I place the coil into the mold. When I cast the bar version, I leave the polypropylene slug in the wound bobbin so that the epoxy doesn't ooze into the slot. This coil hasn’t had the terminals installed yet – I just placed it in there for demonstration. Again, pretend this is cardboard bobbin version.

Next, I pour the West Systems Epoxy. I use black Mixol as a colorant. The whole cast only uses 1/2 teaspoon of material. The c-clamp fixture is intended to keep the sides from flexing – otherwise, the epoxy will just splooch out of the sides. Note the li’l terminals sticking out of the top left corner.

Once the epoxy sets, I pull the bobbin out of the mold and pop the polypropylene plug out with a screwdriver, and voila! A cast bobbin!

This little process I've just illustrated is still under development. I had it working pretty well when I used the Garolite bobbins, but the cardboard, because it is so thin and fragile, presents a few issues I am still in the process of addressing. For one, they tend to bulge a little bit in the middle. At first, I though I could sand the sides down and fine-tune the overall thickness of the bobbin. This is actually a very important step - the bobbin must be just slightly narrower than the magnets so that they protrude ever-so-slightly from the outsides of the bobbin, ensuring firm contact with the poles. But sanding didn't work - I sanded right through the cardboard and ruined the coil. I'm thinking the best solution may be to make a slightly narrower polypropylene slug and therefore have a tighter sandwich when I place the aluminum pieces on the outside when I wind the pickup.

That's it for today. However, I will point out one more slightly unrelated side note about designing sidewinders. One thing I have noticed is that once you get past a certain sweet spot in your wind count, the effect from the amount of additional wire increases drastically. That is, the difference between say, 6000 and 6250 turns or 6000 and 6500 turns is a huge difference when compared to the difference between say 5000 and 6000 turns. (These numbers are just an example and will vary according to the pickup design) I'm not sure why that is. At one point, I liked how the pickup sounded and had been gradually working my wind count up to 6000. I liked it, but I just wanted a little more. I added just a few hundred winds, and then suddenly the pickup was so loud and the attack had become so strong, I thought I was going to blow the speaker on my amp. I decided to wire the coils in parallel instead of series - something I hadn't done before because in the 5000 and 6000 wind pickups, parallel wiring rendered a really weak pickup. But that didn't happen here - the pickup still had plenty of output. Anyway, I thought that was interesting because I have found that when winding a traditional pickup, that effect is less pronounced.

 

[BunchyMutt]

Multi-coil pickups:

I've done a fair amount of development of multi-coil pickups, but I went off in a different direction from what other pickup makers have done. I decided to make long, narrow, tall oval coils that are in line with the strings, like this:

View attachment 3233817

This is the quad-coil pickup that I used in my Series IV model Scroll Basses. Ignore for the moment the funny looking contraption around the bridge. That's the Mechanical Percussive pickup, which is a whole different animal. I'm going to start a separate thread talking just about them. Here, we're talking about the four black oval coils in the foreground.

The main reason I developed this quad-coil pickup is that I wanted to go with a 4" radius fingerboard on this bass. The 4" radius curvature is tight enough that it's really hard to get the pole pieces of even two coils to reach the strings. So, I decided to go with four separate pickup coils, which are individually adjustable in height. This way, I knew I'd be able to dial in the balance between the strings after it was built.

Here's the assembly of the four coils, mounted to a pair of aluminum bars. Each has a vertical travel of about 1/4".

View attachment 3233827

I also wanted this bass to be all passive, and not need any pre-amp to boost the signal levels. The string spacing is 3/4", which doesn't leave room for a round coil with very much wire on it. I wanted the pickups to have enough power and wire turns and resistance to operate on their own, all passive. So, I went with the idea of long oval coils, along the lines of the strings. The coils are each only 5/8" wide, but each contains three 1/4" dia x 3/4" tall Alnico 5 rod magnets. Plenty of magnetic power. The coils are tall and narrow, tight in around the magnets, 5000 turns of #41 wire. The coils end up at about 1.9K ohms each, 7.7K ohms total, wired in series.

I also made them as a full humbucking set. The coils are arranged alternating with the magnets North up and South up, and are wired going opposite directions through the coils. Plus, each coil has a full brass shielding shell around it. They are very quiet, noise-wise.

So, what do they sound like? Actually fairly close to a Seymour Duncan Quarter-Pounder P-bass coil set. A little more powerful. It's the same magnets, 12 instead of 8, all aligned right along the strings. The frequency curve is somewhat flatter than the Duncan QP. Because of the long sensing aperture along the length of the strings, this pickup is completely insensitive to harmonics. It picks them all up equally. When I had this pickup in the test mule, I found that I could move it forward and backward 2" with hardly any difference in sound.

The sensing aperture across the strings is narrower than a QP, because the magnets are directly beneath the string, rather than one on either side. But there are three in line. So, the magnetic field shape around the string is a long tunnel, rather than a wide span. Clarity and definition are a bit higher than the QP, but not a whole lot.

I was using the Duncan QP coils in my Series II and Series III model Scroll Basses, so I have some years of experience with them. The Quad pickup in the Series IV sounds fairly close to the QP coils. That's what I was aiming for, really. The advantage of the Quad is the ability to fit the 4" radius strings with adjustable levels. Plus it's a physically narrow pickup, fitting into the narrow space between the F-holes on the Scroll Bass body.

The downsides to the Quad pickup are cost and weight. It's four complete pickups, expensive to build. And more weight of magnets, wire and epoxy. It's about twice the weight of the QP. It's also kind of tall.

On the drawing board, I have an improved version of the Quad pickup. I'm planning to use it on one of my other upcoming model basses. Four 1/4" magnets per coil instead of three, more compact winding, better design of the bobbins and height adjusting screws. Pushing the idea a little further.

Here are some pictures of the Quad coils under construction:

Cast polyurethane half-bobbins, same process as I described above.

View attachment 3233830

Here's that tight, neat layered winding that I talked about. The opposite of scatter-winding. I make my coils dense and compact.

View attachment 3233831

The wound coil, with the wire ends carefully soldered to the terminals. I then cover them with soft glue.

View attachment 3233832

Potting the coils with CPES epoxy.

View attachment 3233840

The brass shielding shells, with their ground wires soldered to them.

View attachment 3233833

Preparing the shells and coils to go into the housing molds.

View attachment 3233834

Pouring in the black epoxy. West Systems 105/206 with black pigment.

View attachment 3233835

Out of the molds, gluing on the ebony caps.

View attachment 3233836

Final cleanup.

View attachment 3233837

These pictures are all from about 2008, ten years ago. I no longer make the Series IV model, or these particular pickups. But I still have all the tooling and molds. The current pickups I make go through a similar process. I've learned more and made improvements in the manufacturing steps and the pickup design. A lot of R & D work.

Very tidy work.

 

[NKBassman]

Yes, the long oval coils definitely did not dull the high end. I wouldn't say that they boost it either. The main thing I noticed was that the harmonics are all nice and clear and even, at any fret position. Not spikey or very sensitive to pickup location. I also wondered whether the narrower aperture across the strings would cause any problems, but it doesn't seem to. If anything, it increases the definition and clarity. But not by a whole lot.

My understanding is that a single magnet directly under the string creates a nice almost hemispherical magnetic field shape around the string. Fairly compact and concentrated. Really good at detecting the fine movement of the string.

Now, Leo went with two smaller magnets on either side of the string. The magnetic field around the string is a more complicated shape, like a double lobe thing. More concentrated field strength out at the sides and a weaker area in the middle. Why did he do that? I've heard that the main reason was that he wanted to use the same 3/16" magnets as he was using in the guitar pickups, for economy. But the bass pickup needed more magnetic power, so he put in two per string. Or, it may be because the two magnet field makes the sound more thumpy and muddy, less clear and precise. That's what he wanted in his bass sound, at that time. And Fender stuck with that configuration for most of their bass pickups.

Notice that at MusicMan and G & L that changed; they went with single larger magnets directly under the strings. By that time, basses were becoming ping monsters. Clarity and high end became the thing.

So, yes, putting a row of magnets in a line under the string, and angling the line a bit, may be a blend between the two ideas. It could be interesting.

I'd heard that early electric bassists were shredding speakers like it was going out of style, so Fender went from one pole piece under the string to two per string, but offset, in order to reduce the transient spikes from the instrument and make it a little easier on the amps.

 

[Bruce Johnson]

I'd heard that early electric bassists were shredding speakers like it was going out of style, so Fender went from one pole piece under the string to two per string, but offset, in order to reduce the transient spikes from the instrument and make it a little easier on the amps.

I've heard that too. It's possible that was one of the reasons. Although it seems to me that having the two magnets spaced apart might create bigger spikes? But they definitely were having trouble blowing speakers back in those days. That could be the main reason why Leo went with the design of the P-style pickups, making the sound muddier and warmer.

 

[Slidlow]

Probably had a lot to do with the speakers used as well.

 

[Bruce Johnson]

Probably had a lot to do with the speakers used as well.

Yes, speaker design and amp circuit design improved dramatically in the '70's. To keep up with those darn kids and their loud music!

 

[NKBassman]

Probably had a lot to do with the speakers used as well.

Without a doubt.

@Bruce Johnson, I really liked your post on the quad pickups. Thanks for including so much detail, it's a very interesting design.

I've become very sensitive to string-to-string balance on my instruments over the years. I naturally prefer the tone of the P bass, but also really appreciate in no small part having 4 points of adjustment to properly balance the pickup response across the strings.

I've tried many pickups in my Jazz bass over the years, and the last few "flat top" pickups I've tried just didn't cut it. The only thing that's worked for me were Dimarzio Model Js with adjustable pole pieces, or the new Nordstrand J Blades with the radius blade.

 

[Novarocker]

Thank you everyone for all the posts, such interesting discussions! @Freekmagnet I really like the design. I hope all the best in your endeavor, I would certainly love to get my hands on one one day if you decide to make them for customers.

Multi-coil pickups:

I've done a fair amount of development of multi-coil pickups, but I went off in a different direction from what other pickup makers have done. I decided to make long, narrow, tall oval coils that are in line with the strings, like this:

View attachment 3233817

This is the quad-coil pickup that I used in my Series IV model Scroll Basses. Ignore for the moment the funny looking contraption around the bridge. That's the Mechanical Percussive pickup, which is a whole different animal. I'm going to start a separate thread talking just about them. Here, we're talking about the four black oval coils in the foreground.

The main reason I developed this quad-coil pickup is that I wanted to go with a 4" radius fingerboard on this bass. The 4" radius curvature is tight enough that it's really hard to get the pole pieces of even two coils to reach the strings. So, I decided to go with four separate pickup coils, which are individually adjustable in height. This way, I knew I'd be able to dial in the balance between the strings after it was built.

Here's the assembly of the four coils, mounted to a pair of aluminum bars. Each has a vertical travel of about 1/4".

View attachment 3233827

I also wanted this bass to be all passive, and not need any pre-amp to boost the signal levels. The string spacing is 3/4", which doesn't leave room for a round coil with very much wire on it. I wanted the pickups to have enough power and wire turns and resistance to operate on their own, all passive. So, I went with the idea of long oval coils, along the lines of the strings. The coils are each only 5/8" wide, but each contains three 1/4" dia x 3/4" tall Alnico 5 rod magnets. Plenty of magnetic power. The coils are tall and narrow, tight in around the magnets, 5000 turns of #41 wire. The coils end up at about 1.9K ohms each, 7.7K ohms total, wired in series.

I also made them as a full humbucking set. The coils are arranged alternating with the magnets North up and South up, and are wired going opposite directions through the coils. Plus, each coil has a full brass shielding shell around it. They are very quiet, noise-wise.

So, what do they sound like? Actually fairly close to a Seymour Duncan Quarter-Pounder P-bass coil set. A little more powerful. It's the same magnets, 12 instead of 8, all aligned right along the strings. The frequency curve is somewhat flatter than the Duncan QP. Because of the long sensing aperture along the length of the strings, this pickup is completely insensitive to harmonics. It picks them all up equally. When I had this pickup in the test mule, I found that I could move it forward and backward 2" with hardly any difference in sound.

The sensing aperture across the strings is narrower than a QP, because the magnets are directly beneath the string, rather than one on either side. But there are three in line. So, the magnetic field shape around the string is a long tunnel, rather than a wide span. Clarity and definition are a bit higher than the QP, but not a whole lot.

I was using the Duncan QP coils in my Series II and Series III model Scroll Basses, so I have some years of experience with them. The Quad pickup in the Series IV sounds fairly close to the QP coils. That's what I was aiming for, really. The advantage of the Quad is the ability to fit the 4" radius strings with adjustable levels. Plus it's a physically narrow pickup, fitting into the narrow space between the F-holes on the Scroll Bass body.

The downsides to the Quad pickup are cost and weight. It's four complete pickups, expensive to build. And more weight of magnets, wire and epoxy. It's about twice the weight of the QP. It's also kind of tall.

On the drawing board, I have an improved version of the Quad pickup. I'm planning to use it on one of my other upcoming model basses. Four 1/4" magnets per coil instead of three, more compact winding, better design of the bobbins and height adjusting screws. Pushing the idea a little further.

Here are some pictures of the Quad coils under construction:

Cast polyurethane half-bobbins, same process as I described above.

View attachment 3233830

Here's that tight, neat layered winding that I talked about. The opposite of scatter-winding. I make my coils dense and compact.

View attachment 3233831

The wound coil, with the wire ends carefully soldered to the terminals. I then cover them with soft glue.

View attachment 3233832

Potting the coils with CPES epoxy.

View attachment 3233840

The brass shielding shells, with their ground wires soldered to them.

View attachment 3233833

Preparing the shells and coils to go into the housing molds.

View attachment 3233834

Pouring in the black epoxy. West Systems 105/206 with black pigment.

View attachment 3233835

Out of the molds, gluing on the ebony caps.

View attachment 3233836

Final cleanup.

View attachment 3233837

These pictures are all from about 2008, ten years ago. I no longer make the Series IV model, or these particular pickups. But I still have all the tooling and molds. The current pickups I make go through a similar process. I've learned more and made improvements in the manufacturing steps and the pickup design. A lot of R & D work.

This and your subsequent posts have definitely raised an eyebrow for me. It's interesting how balanced you noted the harmonics. I had thought that increasing the length of aperature would increase harmonic content, but goes to show theory is only that, theory.

If I understand what you said, I take it the pickups were thick but very clear?

 

[Bruce Johnson]

If I understand what you said, I take it the pickups were thick but very clear?

What I mean by that is: some warmth (background coloration) in the mid-range, but very clear in the highs and lows. A wide frequency range overall.

 

[Novarocker]

Very cool, goes to show theory only holds up in ones mind. Then the world gets a hold of it haha!

 

[Passinwind]

Although I am still wrapping another pickup project, I kinda started on a new design a few weeks ago. The idea is simple: I want to use some of the extra materials I have laying around and make something cool out of them.

I have a bunch of these 1/4" X 1" neodymium magnets and some really thin pieces of 430 stainless steel. I was hoping to make a really thin humbucker out of these materials. I've built neodymium sidewinders before, and I wasn't completely sold on the sound - I think that the neos in that context rendered a really "peaky" pickup - in other words, the crazy highs of the neos and extra low-end from the big steel blades made both the highs and the lows overwhelming. Instead, I'm going to try this thin steel and see how it works. I'm not sure where this is going, but I'll probably start by wrapping about 5000 turns of 44awg wire around each of the bobbins and see what happens. They may sound kind of tinny, but right now, this is an experiment. If they do work, I might try stacking four of these thin coils to make one quad-coil pickup.

Way cool. My good friend Marco Cortes has been messing around with a new sidewinder format and it looks like I'm going to be the beta tester in the very near future. My context is a fretless four optimized for slide bass duty, a role that my old Travis Bean fretless served very well for a few decades. I asked for "more Manring, less Jaco." It'll be interesting to see how that plays out.

 

[MPU]

Multicoil bobbins continue. I use my drill press with Dremel router bit to shave the bobbins to correct thickness. Then I drill the holes.

I use another jig to glue the washers with CA.

And here they are, bobbins ready for winding.

 

[gyancey]

I took my first dive into casting this weekend. I like the Bartolini BC and P2 sized covers, which I used to be able to get in small quantities but that source has dried up. So I decided to see if I could make my own. The idea was to make a two-part mold and use the "squish" technique, which gives me the option of reproducing the cover itself (if I want to drill for exposed poles) or using the just outside mold to cast an entire coil assembly.

Its definitely a learning experience. I made the mold unnecessarily large, since I had no concept of how stiff the silicone would be on it's own. Didn't need as much margin around the perimeter, so all told this used $60 worth of silicone... Indexing keys didn't need to be as large, and something with a draft angle would have made initial separation easier. Not sure I sprayed enough mold release either, as I lost one positive key that wouldn't come loose.

But, the result from my first pour was pretty encouraging. The original cover I used to make the mold is on the right.

I used a polyurethane casting resin that's already jet black. TC-808 from BJB Enterprises. Need to work on my squish technique though as I did have two troublesome bubbles:

You only get two minutes working time with this stuff, so no time for vacuum degassing! Still though the walls of the pickup shell are pretty thin and I'm impressed with the color and opaqueness of this resin.