That is accepted, a soldering gun has a shorted - almost - secondary.
The planar or similar speakers work by the vibration of an energized coil in a magnetic field, other speakers - say cone types - also work like that.
The all vibrate the air through different shaped surfaces, flat, conical, whatever.
Piezos are different...
What I could not understand is that the amp coupling side is a different subject, the poster wants to essentially print a coil on film, and pass current through it. An acoustic transducer...
How does the use of a transformer help anybody pass current through a coil of this type, it still needs to be connected to an amp, and while you want to use the transformer to do that, the basic need to make a speaker remains.
It seems you want to use it as a coupling transformer of sorts, or for impedance matching.
So your intervention/suggestion was a side topic I think.
The planar or similar speakers work by the vibration of an energized coil in a magnetic field, other speakers - say cone types - also work like that.
The all vibrate the air through different shaped surfaces, flat, conical, whatever.
Piezos are different...
What I could not understand is that the amp coupling side is a different subject, the poster wants to essentially print a coil on film, and pass current through it. An acoustic transducer...
How does the use of a transformer help anybody pass current through a coil of this type, it still needs to be connected to an amp, and while you want to use the transformer to do that, the basic need to make a speaker remains.
It seems you want to use it as a coupling transformer of sorts, or for impedance matching.
So your intervention/suggestion was a side topic I think.
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I will agree though that 0.5um is really painful to work with. It's electrostatically attracted to itself and everything else and it takes almost no effort to rip it.
The key is to tape down one end and very carefully unroll it onto an ultra flat surface like glass and have someone very gently squeegee the air and wrinkles out with their hand as you unroll it.
It will not be perfectly taught and unwrinkled this way but it can be very close.
I would love to know how the factories manage to roll these things up without destroying them. There must be a method to perfectly unroll them as well.
In essence, my goal here is to test how many traces I can possibly fit onto the diaphragm at once and still have it work.
I'm currently searching for a silkscreen transfer method that allows 75 micron resolution (about 3 mils) but more would be better).
The other concern is, since I'm printing some variation of a coil, the silkscreen coil will unravel since there are no supports between traces.
Sorry about that, yeah this is for a pair of headphones. However, if it were not I would still use 0.5 micron mylar. In my experiments I prefer when most of the mass and mechanical strength comes from the Al instead of the mylar. For a speaker I would need to have metallized Al support at the edges if I used 0.5um mylar.
I will agree though that 0.5um is really painful to work with. It's electrostatically attracted to itself and everything else and it takes almost no effort to rip it.
The key is to tape down one end and very carefully unroll it onto an ultra flat surface like glass and have someone very gently squeegee the air and wrinkles out with their hand as you unroll it.
It will not be perfectly taught and unwrinkled this way but it can be very close.
I would love to know how the factories manage to roll these things up without destroying them. There must be a method to perfectly unroll them as well.
In essence, my goal here is to test how many traces I can possibly fit onto the diaphragm at once and still have it work.
I'm currently searching for a silkscreen transfer method that allows 75 micron resolution (about 3 mils) but more would be better).
The other concern is, since I'm printing some variation of a coil, the silkscreen coil will unravel since there are no supports between traces.
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My apologies, my spell-checker types "delta" when I meant "DECCA". Prolly didn't confuse any experienced readers.
I can't tell if you are unfamiliar with the Decca ribbon (which used a transformer for impedance matching) that astounded audiophiles around the world long ago, or are just "saving face" and wasting bandwidth? If the first, just google "Decca ribbon" and all will become clear to you.
For sure long ago, a transformer was a good design choice for a tiny accordion ribbon (that blew up regularly) with a horn. Whether it "computes" for anything larger, I hope other smarter folks can judge.
B.
At your first mention, I did look at the Decca ribbon, something new for me.
Yes, it had a transformer, used to match impedance. I mentioned that in my post.
Now it is becoming clear that the OP wants to build planar headphones, and it will be difficult to hold the film while working on making it..
Headphones fed through a transformer will be difficult I think, and a little, let us say ...bulky?
A suggestion to the OP: look at corona discharge units and static eliminators, or buy corona treated film, which is done at the extrusion stage for film intended to be printed upon.
That won't stick to itself.
Yes, it had a transformer, used to match impedance. I mentioned that in my post.
Now it is becoming clear that the OP wants to build planar headphones, and it will be difficult to hold the film while working on making it..
Headphones fed through a transformer will be difficult I think, and a little, let us say ...bulky?
A suggestion to the OP: look at corona discharge units and static eliminators, or buy corona treated film, which is done at the extrusion stage for film intended to be printed upon.
That won't stick to itself.
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BTW, the Decca ribbon was a tweeter with a rather high band. A transformer would be much larger for lower frequencies.
No you don't need to mount the transformers on top of your head if we are talking about headphones. Or is this thread deteriorating into jokes?
I know the Decca ribbon was a tweeter.
The reason for headphones is ease of carrying them around, privacy and so on.
A transformer would reduce that. It can be anywhere suitable on the leads, as convenient.
No need to put on the head, sorry you did not understand that. But you will need to carry it around to use at different places.
And since headphones use a lot less power than regular speakers, designing and making a suitable transformer will be an additional task, will it not?
But I have seen new chips designed for car amps specified for 1 - 4 ohm loads. So maybe no need for transformer.
The reason for headphones is ease of carrying them around, privacy and so on.
A transformer would reduce that. It can be anywhere suitable on the leads, as convenient.
No need to put on the head, sorry you did not understand that. But you will need to carry it around to use at different places.
And since headphones use a lot less power than regular speakers, designing and making a suitable transformer will be an additional task, will it not?
But I have seen new chips designed for car amps specified for 1 - 4 ohm loads. So maybe no need for transformer.
If you stretch the metalized mylar foil (with etched pattern), the aluminium traces will probably break.
I also wanted to make a new diaphragm for my Technics EAH-820 orthodynamic headphones. I have some metalized food wrapping foil. My plan was to use PCB photoresist lacquer (Positiv-20) spray that can be used under UV lamp, then etched by NaOH. I wanted to use the original diaphragm as a master, then do some retouching under magnifying lens. Still on my todo list...
I also wanted to make a new diaphragm for my Technics EAH-820 orthodynamic headphones. I have some metalized food wrapping foil. My plan was to use PCB photoresist lacquer (Positiv-20) spray that can be used under UV lamp, then etched by NaOH. I wanted to use the original diaphragm as a master, then do some retouching under magnifying lens. Still on my todo list...
This project will need some serious ingenuity, and the results will be disappointing.
If you are able to make a fixture to hold the film taut, until final mounting, through all the working steps, then you can complete this project.
Embroidery frames come to mind.
Or simply value your own time, and buy ready made headphones of your choice.
If you are able to make a fixture to hold the film taut, until final mounting, through all the working steps, then you can complete this project.
Embroidery frames come to mind.
Or simply value your own time, and buy ready made headphones of your choice.
It's only going to be that strong within the gap. Strength will drop rapidly outside it.
I think the size of the MRI's field drives a lot of the extreme measures, along with the need to create non-static fields (oscillating and gradient).
https://www.hsmagnets.com/blog/how-strong-are-speaker-magnets/"Speaker magnet strength ranges from about 0.001 tesla all the way up to about 1.5 tesla (the strongest neodymium magnets)."
https://www.kjmagnetics.com/blog.asp?p=gap-calculator"The calculator shows the field strength at a point in the middle, between the two magnets. It also graphs the field strength (for the portion of the magnetic field that is in the vertical direction) across the diameter of the magnet.
It’s possible to achieve field strengths up to 10,000 – 12,000 gauss (1.0 - 1.2 Tesla) with small gaps, especially if using magnets that aren’t too thin."
https://en.wikipedia.org/wiki/Tesla_(unit)"The strongest fields encountered from permanent magnets on Earth are from Halbach spheres and can be over 4.5 T."
Those magnets will fit headphones?
I did not read the linked articles...
And if yes, another test of ingenuity to fix the film in the magnetic field, with a narrow gap.
I did not read the linked articles...
And if yes, another test of ingenuity to fix the film in the magnetic field, with a narrow gap.
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Have you decided how you're going to get a reasonably flat magnetic field that's transparent and rigid? IFAIK that might prove to be quite difficult. You need a Bl of around 5 minimum I would imagine - that makes for very many turns of wire that don't cancel each other out or very high B. The reason why the Decca transformer was not such a bad idea, is that the force is of course Bli, and increasing i is a good idea. These headphones of yours will most probably be a beast to drive, but that's OK. Reading through the discussion, I'm beginning to see why people make electrostatics though... ;-)
Yes. A surface field of 5-6000 guass is pretty easy to find for single small neodymium magnets. The rest is supposed to be from their Fluxor magnet arrangement, which concentrates and linearizes the field in the gap.
Mylar has the somewhat annoying, (or useful) habit of shrinking with heat.
Stretch mylar loosely but taut enough to be wrinkle free, and carefully shrink with a hair dryer or heat gun on low temperature.
At least thats how the RC plane builders use self adhesive mylar. The thickness of that may even be good enough
I think this thread got derailed. Why are we talking about ribbons and transformers?
On another note, I'm looking at CO2 laser cutting and CNC milling and they seem to have a 50 micron tolerance. Might be worth looking into for making a stencil.
The problem I'm having right now is the 75 micron traces I desire require resolutions too small for silkscreen methods that I can find.
On another note, I'm looking at CO2 laser cutting and CNC milling and they seem to have a 50 micron tolerance. Might be worth looking into for making a stencil.
The problem I'm having right now is the 75 micron traces I desire require resolutions too small for silkscreen methods that I can find.
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Oh damn, I think I solved it.
https://www.stencilsunlimited.com/s...cqaL1ZDalKotgIqeG-Gw96TT8afMHy3waAuoKEALw_wcB
Custom stencil service for vapor deposition. Hopefully they don't charge too much.
https://www.stencilsunlimited.com/s...cqaL1ZDalKotgIqeG-Gw96TT8afMHy3waAuoKEALw_wcB
Custom stencil service for vapor deposition. Hopefully they don't charge too much.
I think a clearer first post would have helped to filter the suggestions made here by different members.
Good luck.
Keep us posted.
Also, look at the methods used by Kristeel Shinwa and others for making springs for watches and so on.
They have laser and acid etching processes available, they make tiny metal parts.
Those might be useful in making the fine patterns you need.
Maybe other processes too, the watch movement business has some very close tolerance work done in high volumes, particularly as the price is so low...Miyota 2035 movements go for 60 cents, wholesale.
That is a watch movement, and Miyota is/was the parent company of Citizen watches.
The drawings show tolerances of less than one micron, you are seeing 50 microns from CO2 laser services.
Good luck.
Keep us posted.
Also, look at the methods used by Kristeel Shinwa and others for making springs for watches and so on.
They have laser and acid etching processes available, they make tiny metal parts.
Those might be useful in making the fine patterns you need.
Maybe other processes too, the watch movement business has some very close tolerance work done in high volumes, particularly as the price is so low...Miyota 2035 movements go for 60 cents, wholesale.
That is a watch movement, and Miyota is/was the parent company of Citizen watches.
The drawings show tolerances of less than one micron, you are seeing 50 microns from CO2 laser services.
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And the thinnest they can do is 0.02 inch = 50 micron!
That 100x thicker as in your first post.
That's for the stencil to draw the chemical resist, not the diaphram.
However, I've decided to build a magnetron sputtering system instead of etching materials with chemicals because it's way cooler and ultimately better.
I'll be documenting that progress in this thread
https://www.diyaudio.com/community/threads/diy-magnetron-sputtering-machine.382578/#post-6928332