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Author Topic: Gold sputtered 3 micron polyester!  (Read 3421 times)

Offline argibbo

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  • Real Full Name: Andy Gibbons
Gold sputtered 3 micron polyester!
« on: December 02, 2012, 11:29:44 am »
Hi again chaps.

I've been building a large capsule condenser mic over the last 4 years. I'm still stuck for the gold sputtered mylar. Any ideas? So far I have the body, valve electronics and the capsule built. I've skinned it with 20 micron aluminium film and have actually had sound from it, though it does sound a bit 'telephonic'.

Hopefully, as part of my university course, they will let me build the power supply as a project. (Going for the Sony C37 PSU, early type, because it has valve rectification) Does anyone know the HT voltage output from that PSU?

Best regards

Andy

Offline Jim Williams

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Re: Gold sputtered 3 micron polyester!
« Reply #1 on: December 03, 2012, 11:25:17 am »
If you can't find a source for it, you can buy an aftermarket capsule for pretty cheap. A C-12 knock-off capsule is about a hundred bucks. Remove the diaphram and you may be able to remount it. Without a very good lab and expensive machining and testing equipment you may find your design a few decades behind the ball.

Four years? Isn't that about the amount of time some reknowned mic "moders" take your mic away from you? I'm also curious about a course in a university that lasts for four years too, what school is this?

Offline ratite

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Re: Gold sputtered 3 micron polyester!
« Reply #2 on: December 04, 2012, 07:34:56 am »
Bit of info here: http://repforums.prosoundweb.com/index.php?topic=31220.0
There is a link in the thread on DIY vacuum evaporation/deposition of gold and nickel on membranes.

Offline Tim Campbell

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  • Posts: 23
Re: Gold sputtered 3 micron polyester!
« Reply #3 on: December 05, 2012, 02:32:41 am »
If the microphone capsule currently doesn't sound good then you have more work to do with your capsule before worrying about the final film you will need for the membrane.

Get yourself a capacitor that's large enough and contains 5-6 micron thick aluminum metalized foil. This will give you plenty of material for experimenting with. Try various tuning frequencies and spacing arrangements. Perhaps your backplate design isn't good enough.

Is this mic multipattern? Fig.8?