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Cycfi

Hexaphonic Pickup Project

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Sounds good. I'll give it a try when I get a chance. FEMM is indeed interesting. BTW, are those vertical ferrite bars between the coils?

There's no space there anymore, but there might be in front and behind the coils. It's also interesting how some space between the magnet and the ferrite affects the whole.

No, just steel. I know proportions and details aren't exact, but it's a rough idea. To be honest, FEMM isn't going to simulate a pickup. There are much more complicated things going on, in 3D and AC. It can help you visualize the basics though. What your looking at, there are six coils with smaller metal rods between them. The rods are much darker than the ferrite core of the inductors. The two smaller boxes on the outsides of the pickup are the adjustment screws, or a representation of them.

DarkAvenger, could you remind me what exactly are we aiming at? Cross-talk? SNR? I believe I nailed the SNR issue and recent experiments reveal that I am already getting -38db cross-talk. I am looking into smaller magnets and coils plus mu-metal shielding to further reduce cross-talk.

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Getting more out of less. That's great with the SNR. If you could get more signal out of the coil with less noise, couldn't you use a more power efficient opamp? Also, reducing string pull is always a good thing.

I guess I'm just giving you suggestions. I would also advise against mumetal at first, unless you have a source already. I've experimented with it and while it does help, I think you would benefit more from the overall magnetic design rather than jumping to mumetal. Certain stainless steels work well for this application and are easy to find.

Also, I'm not suggesting anything too radical, just some simple experiments you could try. As I've said before, these modifications will need to be tuned to what your trying to do. The quickest and easiest way of doing this is with a few tests.

Food for thought:

Simply put, Inductance = Permeability x ((#Turns^2 x Area of core) / Length of coil)

Neo magnets have a relatively low permeability but strong field strength.

Shielding is merely an easy path for the magnetic field to travel back to the other pole.

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Getting more out of less. That's great with the SNR. If you could get more signal out of the coil with less noise, couldn't you use a more power efficient opamp?

Well, yes and no. The self noise of the Op Amp is the lower limit. It turns out that I've also reached the optimal self-noise with 1.0 and that there are more noise elsewhere that it makes sense to relax the Op Amp specs. Hence in 1.1, I'm using a lower power Op Amp with 150uA quiescent current. This issue has been discussed thoroughly in this thread.

Also, reducing string pull is always a good thing.

Yep. Agreed. That is why I have to back off the Neo a bit. Right now, at 2000 turns (450 Ohms DCR), the raw output of the coil is 1/4th that of a Strat. Not bad at all for a low impedance coil! So I only need to have a gain of 5 for the active electronics.

I guess I'm just giving you suggestions. I would also advise against mumetal at first, unless you have a source already. I've experimented with it and while it does help, I think you would benefit more from the overall magnetic design rather than jumping to mumetal. Certain stainless steels work well for this application and are easy to find.

I want to use mu-metal foil with adhesive backing. What's nice about them is that I can cut and use them as shields around the coils to minimize fringe flux and hence crosstalk. You can also find mu-metal tapes, although that's very difficult to find. SS sheets OTOH are very difficult to deal with. Mu-metal is more ductile and workable, allowing it to be easily formed into the thin sheets.

Also, I'm not suggesting anything too radical, just some simple experiments you could try. As I've said before, these modifications will need to be tuned to what your trying to do. The quickest and easiest way of doing this is with a few tests.

Food for thought:

Simply put, Inductance = Permeability x ((#Turns^2 x Area of core) / Length of coil)

Neo magnets have a relatively low permeability but strong field strength.

Shielding is merely an easy path for the magnetic field to travel back to the other pole.

Yes, I am well aware of that.

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Well, I was actually thinking about using a few small pole pieces that could be soldered into the board on either side of each coil. Mumetal tape will saturate very quickly, so it may need to be thicker to effectively shape a magnetic field.

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Well, I was actually thinking about using a few small pole pieces that could be soldered into the board on either side of each coil. Mumetal tape will saturate very quickly, so it may need to be thicker to effectively shape a magnetic field.

Nods. I think that is a good idea. I shall try that. I'll also try the idea of using field repulsion using magnets as mentioned here.

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Hi there! So, we’ve been busy. It’s been a while, but we are inching slowly, but surely, towards production. Let me present the Six Pack Production prototype (v1.4).

Check it out.

hex-1.4-with-cover-small.jpg

Six Pack 1.4

hex_v1_3.jpg

Six Pack 1.4 Assembly

Edited by Cycfi

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Unbelievable. How do they sound now? Any tweaks since last time?

Sound clips coming... Anyway, it's basically the same configuration as before. The changes are mostly for ease of production. We spent more time with logistics: dealing with manufacturers and the supply chain, esp. with the custom designed coils. There were at least four iterations in the coil design until we finally settled on what we have now.

Let me reveal a little secret though: We achieved polyphonic infinite sustain using the PUs. I thought I'd inform this forum. It's still early in the development, but it's working! I'm very excited about it :-) I'll start a new thread for this new project I call "Infinity".

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Wow! This is so many levels of wrong. Fantastic news Joel! Never been a sustainer user but you might tempt me.

Haha. So what do you exactly mean by "so many levels of wrong"? :-) Is it because this is sort of a taboo subject here (talking about sustainers?)

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Oh no, just a turn of phrase! A completely unbelievable result. Something this awesome should not exist. Nature should not allow it.

I love it in black.

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Hi again,

It's been a while. It took quite a bit of time to get it in the production stage. This is actually our first time to get something produced in quantity. The project has evolved into what we call the Neo Polymorphic Pickup Series. Small, Modular Active Polyphonic Pickups.

(To the mods, this project grew up on this forum (among other forums) and I am very thankful for the nice people here especially for the support and participation in getting this realised. I've hesitated posting here because I've come to the point where the project is actually ready to go commercial (very limited production for now) and I fear being flagged as spam. For what it's worth, the project is still 100% open source and the designs are freely shared, BOM, schematics, layout and all.) I'd like to continue posting here, but if you think it is inappropriate, please advise.)

So here's the latest production-ready version:

neo-series.jpg

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Here are some sound clips:

http://www.cycfi.com/projects/neo-series/sculpting-the-tone/

In the demo, I took advantage of the flat frequency response to sculpt the tone using EQ matching in the DAW where I capture the EQ of another guitar (e.g. classical guitar, Les Paul, EMG-81) and match and apply it to the Neo pickups. The results are very interesting!

Edited by Cycfi

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It's always good to see what is next out of your projects, Joel. Open source "white box" projects are certainly the most educational and a driver for continued innovation. The guitar industry is still very much stuck using 50s technology and it really shouldn't be so.

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A friend of mine suggested having transparent pickup covers for the Neo6 pickups. I think it’s a good idea. If there’s interest, we might be able to provide these covers as an option. The coils will be encapsulated in either clear or tinted epoxy. Tell us what you think!

trans_pup.jpgtrans_pup_back.jpg

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Hi Y'all,

I just posted a new project in this forum:

It's the start of what I've been alluding to at the very start of this thread: an infinite sustain system. I'm VERY excited about this one. Like before, I would very much love to hear your thoughts and gather ideas while the project evolves!

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Hei Joel! I was just about to say this exact same thing....I'd even pinned the email notifier to remind me to do this once I was at the desktop. Thanks for checking in and pipping me to the post. :thumb:

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4 hours ago, Prostheta said:

Hei Joel! I was just about to say this exact same thing....I'd even pinned the email notifier to remind me to do this once I was at the desktop. Thanks for checking in and pipping me to the post. :thumb:

Hi Carl,

My pleasure, Carl. This forum is special. This is where my journey started. Thank you very much for all your support and enthusiasm!

Actually, I hesitated a bit, fearing my reply might be construed as self serving advertising. I've been less active in forums since we started going commercial (but just enough to sustain R&D), although we're still 100% open source, with all the designs shared in GitHub for everyone. Some forums have very strict guidelines against sharing links. I would certainly love to post updates every once in a while if you allow me to (e.g. the Infinity Project).

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I understand that you're super short on time Joel, so it's all cool. I've been very interested in your system for a while, so it's been great seeing it develop, especially with it being open source. That way I can see how it is developing! Very educational.

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Hello Joel,

I know I've arrived pretty late to this train, the six-pack being superseded by Neo (I've read lots of interesting material about the design and development, and can't be thankful enough for making it available, along with the hardware plans).

I'd have a question about the original Six-Pack design: do you happen to have, and could you give any more details about the coil wire used for the six-pack coils? I remember reading somewhere that it was 46AWG, and (based on the final design) it had 2000 turns with a 450ohms impedance. I'm trying to build something similar and I am searching for the best wire to do it, and can't tell what material and what resistance properties to choose (860 Ω/m NICHROME Nikrothal and 362.4 Ω/m MANGANIN CuMn12Ni would be the ones easily available - the nichrome has more than double resistance, so I'd probably need less of that, meaning smaller coils) ?

Regards,

Robert

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On 8/9/2019 at 11:15 AM, evfool said:

I'm trying to build something similar and I am searching for the best wire to do it, and can't tell what material and what resistance properties to choose (860 Ω/m NICHROME Nikrothal and 362.4 Ω/m MANGANIN CuMn12Ni would be the ones easily available - the nichrome has more than double resistance, so I'd probably need less of that, meaning smaller coils) ?

Ignore the Manganin and Nikrothal option, those probably won't work in pickups (electromagnets) as they don't have any magnetic attraction.

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