DIY large condenser capsules using PCB + space blanket

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Dec 5, 2021
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Cambridge UK
I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!
 

frobozz

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Mar 12, 2021
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Location
Italy
I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!
great project, what is the right "search" for the aluminiumised Mylar ? I have difficult to find it
 

kingkorg

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Apr 15, 2017
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I've had some success with homebrewing large condenser capsules. I wanted to experiment with different capsule shapes and backplate hole layouts, so needed a very cheap method of building them. I also don't have a micrometer tolerance lathe.

After quite a few iterations, I've had some reasonable results with using copper-clad PCB and aluminiumised Mylar in the form of a cheap space blanket.

I've written it up as an Instructable: DIY Large Diaphragm True Condenser Microphone Capsule - From Scratch!
Thanks a milion for this space blanket tip, quite nice material!!! Do you have any idea what the thickness is, or can you find out? I have some 5 micron stuff, this feels thicker.
 
Joined
Dec 5, 2021
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9
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Cambridge UK
I managed to get hold of a micrometer and measured it at 6µm.

I've found that sticking the conductive side to the faceplate seems to get better results than sticking the non-conductive side to the edge of the backplate.

If you're struggling with corners buckling up, then you can modify the design so that the backplate active area feeding copper trace comes off a side rather than a corner.
 

Pariah Zero

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Jul 12, 2022
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28
Location
Intermountain West, USA
Before I saw this thread, I've been thinking about doing something very similar:

  • The idea of using a PCB/perfboard for a backplate is a great one. I'm glad you shared it.
  • I'm also glad I've got confirmation that a space blanket can work
    • I thought it would, and since aluminum doesn't corrode that readily, it seemed to be a decent substitute vs gold-coated mylar, especially since a maintenance reskin wouldn't be an issue.
  • I've got a micro lathe, so I was going to use Aluminum stock to turn out a capsule - consciously avoiding brass because it makes a bit more mess than I'm willing to deal with at the moment...
It gives me some ideas to chew on while I work on my ribbon mic; hopefully I'll have something to show in a month or two.

The other big question is if it's going to be worthwhile to try to find something on Alibaba (I'm not sure I could use 1 kg)

It does remind me that I have (or at least used to have) some 47 µF polypropylene foil capacitors. Those things are filled with 6µm aluminized film, and a 47µF film capacitor ain't small. I seem to recall they're about 62mm long and 62mm in diameter, so there may be plenty of foil to be had... definitely worth a search. If not, well, for anybody interested, and I can find the buggers, I'll let you know if the film is useful - if so, you know where to get plenty.
 
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