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Magnets & Copper Wire: A Pickup Building Thread
- Thread starter Freekmagnet
- Start date
With two volume controls, you may run into decreased hum bucking ability - as you turn one volume either higher or lower than the other. Of course, with my preferred control setup - master volume and blend, as I turn the blend control away from the center, I also lose hum bucking ability.
Take a look at the Peavey T-45. Single humbucker. It has a master volume, master tone control, and a second volume control that pots down one of the pickups (off the white wire in the diagram below), effectively transitioning between humbucking, non-humbucking, and whatever in between.
(EDIT: Reflecting what @dwizum says below about differences in each pickup's output, there's not much audible change through most of the second volume pot's travel here. iirc only the last 30%. It's possible that a different taper could've evened it out more, but I assume the designer had tried what was available at the time before signing off on this.)
(EDIT: Reflecting what @dwizum says below about differences in each pickup's output, there's not much audible change through most of the second volume pot's travel here. iirc only the last 30%. It's possible that a different taper could've evened it out more, but I assume the designer had tried what was available at the time before signing off on this.)
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Polarity for the signal produced by the strings is impacted by both magnet polarity and coil direction. Polarity for noise signals is only impacted by coil direction. Hence, RWRP means the signal will be in phase (it's reversed twice) but noise will be out of phase (it's reversed once).
So, if you're winding two single coils, it makes sense to make them RWRP, since you'll get an in phase string signal and an out of phase noise signal.
For the out of phase noise signal to cancel itself as completely as possible, it's ideal to have the same number of turns on the coils. However, it's not critical to get an exact match. It's typical for a bridge pickup to have more turns than a neck pickup. Even as much as a 30% difference in turn count doesn't really show up as a noise problem, in my experience.
If you have volume controls on each pickup separately, then the noise cancelling will be best when they're at the same volume setting. If they are at different settings, the noise signal will increase as the settings become further apart. Again, though, it takes a pretty big difference to make the noise signal significant.
So, if you're winding two single coils, it makes sense to make them RWRP, since you'll get an in phase string signal and an out of phase noise signal.
For the out of phase noise signal to cancel itself as completely as possible, it's ideal to have the same number of turns on the coils. However, it's not critical to get an exact match. It's typical for a bridge pickup to have more turns than a neck pickup. Even as much as a 30% difference in turn count doesn't really show up as a noise problem, in my experience.
If you have volume controls on each pickup separately, then the noise cancelling will be best when they're at the same volume setting. If they are at different settings, the noise signal will increase as the settings become further apart. Again, though, it takes a pretty big difference to make the noise signal significant.
Thanks everyone!
So, my take away from all your responses...
-RWRP is the way to go; only RW would be humbucking, but the signal produced by each pickup would be out of phase with each other.
-I can increase the winds on the bridge pickup (this was my intention) and still get the noise-cancelling benefits.
-independent volume controls will have some effect on the noise, but the effect may be negligible. Possible work around: master volume and blend knob.
-also, check out Peavey passive circuits, T40 specifically.
So, my take away from all your responses...
-RWRP is the way to go; only RW would be humbucking, but the signal produced by each pickup would be out of phase with each other.
-I can increase the winds on the bridge pickup (this was my intention) and still get the noise-cancelling benefits.
-independent volume controls will have some effect on the noise, but the effect may be negligible. Possible work around: master volume and blend knob.
-also, check out Peavey passive circuits, T40 specifically.
slowburnaz
Commercial User
Playing around with another design, and thought I'd try a simple 3D render of it... wanted to see if there was a built-in way to do a cut-away view in Fusion 360. There isn't, at least as far as I can find, but I did figure out a way to do it.
This is a pickup style I'm thinking of doing for the Bart BC and P4 sized routes:
This is a pickup style I'm thinking of doing for the Bart BC and P4 sized routes:
For a "simple 3D render", that's impressive. The materials, reflections, and shadows are good. If you hadn't said so, I'd have taken it for a photo... maybe slightly touched up. I got off the Autodesk bus years ago. Didn't know Fusion 360 had that capability.
Cool design. External form reminds me a little of Peavey Super Ferrites. Individual-coil designs intrigue me, especially when there's an even number of them.
Cool design. External form reminds me a little of Peavey Super Ferrites. Individual-coil designs intrigue me, especially when there's an even number of them.
slowburnaz
Commercial User
Ha! Well, all I did was pick a default lighting scene, position it, and click the render button.
Fusion 360 did all the real work.And yeah, I was going for a bit of a Super Ferrite/Greco GOB Speedway pickup aesthetic, but with a sorta standardized shape/size.
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I wondered how much setup you had to do re: materials, light sources, background, etc. Good defaults, I'd say.
Hi!
Might not be what you're looking for, but if you turn all parts into components, you can "explode" them in the Animation tab if I'm not mistaken. Not a cut-away view, but might come in handy
You know, you could probably make some money selling your computer models of pickups to folks who want to "build" their own computer models of basses.....Complete with a synthetic sound track. Virtual Pickups.
Oh yeah . They would Sell like virtual hot cakes , nice job seriously...
We Luthiers will be seeing a lot more of this virtual design stuff. Customers with good computer skills will design their own dream bass as a complete computer model. Then they will send the model to Luthiers for a quote on building it....exactly to their model. We can do it, but they will be surprised at the price. It's a whole lot of extra labor and risk to build to a full model, getting every single dimension exactly right to their satisfaction. And a Luthier with a CNC router wouldn't necessarily be cheaper.
The same thing may happen with pickups. A customer may design up their dream pickup in a full 3-D model, complete with cool cutaways, then send the model to Chris for a quote on making one.
The same thing may happen with pickups. A customer may design up their dream pickup in a full 3-D model, complete with cool cutaways, then send the model to Chris for a quote on making one.
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slowburnaz
Commercial User
Yup. And not to mention the amount of troubleshooting involved when either the model has screwy dimensions, or what they're trying to do works fine in the model, but is non-sensical or ill-advised IRL.
You can imagine the fun when a customer sends you a computer model of a cool looking multi-coil pickup, then pays you $500 to build one. And when they get it, it doesn't sound "right". Obviously, you didn't build it right, following their model! Hilarity ensues.
Thanks everyone!
So, my take away from all your responses...
-RWRP is the way to go; only RW would be humbucking, but the signal produced by each pickup would be out of phase with each other.
-I can increase the winds on the bridge pickup (this was my intention) and still get the noise-cancelling benefits.
-independent volume controls will have some effect on the noise, but the effect may be negligible. Possible work around: master volume and blend knob.
-also, check out Peavey passive circuits, T40 specifically.
You can increase the winds on one bobin and still get some hum cancelling benefits. The more you increase the difference between the two bobins, the more hum you'll get.
Same for the volume (or blend, it's pretty much the same, not a work arround), if you turn the bridge volume down, hum will start to apear en the neck pickup sound. When you roll one of the volumes completely off, the hum is like that of any singlecoil.
I have a jbass set like this and mostly I use just the neck pickup alone or with the bridge pickup just slightly blended in, and the hum is there but normally doesn't bother me. If for some reason I have to play in a more noisy environment where hum becomes an issue, I can blend in the bridge pu to cancel it; but the tone of both pickups on full is not my favourite, so its a compromise situation.
Here's a housing mold set that I just completed for Jeremy. This is for casting the external shell of his Pistolera model pickups. He gave me an Acad drawing of the external shape and dimensions.
The first step is to make up a Master; an actual size final shape of the pickup. I like to machine the masters from aluminum for durability, but masters can be made from wood or plastic too. They just need to be accurate in dimensions and smoothly finished.
I start with a chunk of 1 1/2" square 6061 aluminum bar stock, sawn off to length. I use the big Kondia milling machine to hog off the excess aluminum and bring the rectangular pickup to size and shape.
I leave a rectangular flange at the bottom, to help with casting the silicone mold.
I forgot to photograph a couple of steps, but there's the finished master. I used my smaller mill to drill the holes for the screws all the way down through with a #30 bit. Small counterbores at the top to recess the screw heads. These holes and counterbores will be created accurately during the pickup casting process. He won't have to drill them after casting.
I hand filed small radiuses on the corners and edges, to his drawing, and block-sanded the flat surfaces to 400 grit. Jeremy said it wasn't necessary to go to a full polish on this one.
The part in the front is the base plate for the silicone mold. It holds the two pins in accurate position during the casting. The base plate is a piece of 1/4" x 1 1/2" aluminum bar stock. The hole locations are transfer punched from the master. The pins are cut from 1/8" steel rod stock, rounded on the ends.
I ripped a strip of 3/4" MDF and cut it into four blocks that fit tightly into a box around that bottom flange of the master, like this.
I waxed the faces of the MDF blocks and clamped them around the master, on a sheet of waxed paper. The pins are also waxed and inserted in the holes in the master. Then I mixed up the silicone mold making compound and poured it in the box, up to the top edge.
I like Smooth-On's Mold Max 30 silicone compound. It's kind of slow curing, about 12 hours, but bubbles work their way up and out in open air curing like this. For most things like this, it doesn't need to be put in a vacuum chamber. It's simple and reliable.
The next day, I pulled the mold off of the master, no problem.
Now I fit the pins into the base plate. I drilled those holes 1/8", so the pins are a light hammer-tap friction fit.
The mold then slips down over the pins. The base plate holds the pins at an accurate dimensional spacing and straight vertical during the casting. You can see the little bump in the silicone around the pin that creates the counterbore.
And here's the finished mold kit going to Jeremy. The master, the mold, and the wood blocks. This mold will probably be good for 50-100 pickups. When it wears out, he can easily pour a new mold using the master and the wood blocks.
I'm showing all of you this to encourage you to try this for yourselves, for own pickup making projects. Don't be intimidated by my milling machines and aluminum masters. You can make the masters by gluing them up from blocks of maple or plastic, and hand filing them to shape. Pouring silicone molds and casting pickups in poly resin or epoxy is easy to do in a small shop.
The main thing I'm showing here is the trick of using the steel pins and aluminum base plate with the silicone mold, to make accurate screw holes in your castings. You can do that with a drill press.
The first step is to make up a Master; an actual size final shape of the pickup. I like to machine the masters from aluminum for durability, but masters can be made from wood or plastic too. They just need to be accurate in dimensions and smoothly finished.
I start with a chunk of 1 1/2" square 6061 aluminum bar stock, sawn off to length. I use the big Kondia milling machine to hog off the excess aluminum and bring the rectangular pickup to size and shape.
I leave a rectangular flange at the bottom, to help with casting the silicone mold.
I forgot to photograph a couple of steps, but there's the finished master. I used my smaller mill to drill the holes for the screws all the way down through with a #30 bit. Small counterbores at the top to recess the screw heads. These holes and counterbores will be created accurately during the pickup casting process. He won't have to drill them after casting.
I hand filed small radiuses on the corners and edges, to his drawing, and block-sanded the flat surfaces to 400 grit. Jeremy said it wasn't necessary to go to a full polish on this one.
The part in the front is the base plate for the silicone mold. It holds the two pins in accurate position during the casting. The base plate is a piece of 1/4" x 1 1/2" aluminum bar stock. The hole locations are transfer punched from the master. The pins are cut from 1/8" steel rod stock, rounded on the ends.
I ripped a strip of 3/4" MDF and cut it into four blocks that fit tightly into a box around that bottom flange of the master, like this.
I waxed the faces of the MDF blocks and clamped them around the master, on a sheet of waxed paper. The pins are also waxed and inserted in the holes in the master. Then I mixed up the silicone mold making compound and poured it in the box, up to the top edge.
I like Smooth-On's Mold Max 30 silicone compound. It's kind of slow curing, about 12 hours, but bubbles work their way up and out in open air curing like this. For most things like this, it doesn't need to be put in a vacuum chamber. It's simple and reliable.
The next day, I pulled the mold off of the master, no problem.
Now I fit the pins into the base plate. I drilled those holes 1/8", so the pins are a light hammer-tap friction fit.
The mold then slips down over the pins. The base plate holds the pins at an accurate dimensional spacing and straight vertical during the casting. You can see the little bump in the silicone around the pin that creates the counterbore.
And here's the finished mold kit going to Jeremy. The master, the mold, and the wood blocks. This mold will probably be good for 50-100 pickups. When it wears out, he can easily pour a new mold using the master and the wood blocks.
I'm showing all of you this to encourage you to try this for yourselves, for own pickup making projects. Don't be intimidated by my milling machines and aluminum masters. You can make the masters by gluing them up from blocks of maple or plastic, and hand filing them to shape. Pouring silicone molds and casting pickups in poly resin or epoxy is easy to do in a small shop.
The main thing I'm showing here is the trick of using the steel pins and aluminum base plate with the silicone mold, to make accurate screw holes in your castings. You can do that with a drill press.
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