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What should follow an electret mic capsule?
Old 12th July 2013 | Show parent
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Richard Crowley's Avatar
🎧 10 years
Originally Posted by oneoldude ➡️
The X-R does not and you can see the capsule case sticking out of its holder. Here is their pic.
It is not clear from the photo (at least to me) whether that is the raw capsule or not. The raw capsule with the fake-fabric dust cover is quite mechanically vulnerable and I would not sell it as a commercial product without better protection.

I will face EMI issues. But how bad will they be? I guess I can only build it and and see.
IME, without a proper Faraday shield around it, using the shell of the capsule as the input to your buffer will yield noise so bad you won't know whether the mic capsule is even working. It will be completely and obviously unusable.

That would put the case at ground and should be a whole lot better re: EMI if I have done it right. Of course, doing it this way negates the beauty of using an un-cut case and still get the benefits of a cut case. But, in engineering as in life, everything is a compromise.
If you have several "spare" capsules, I would keep your "reference capsule" un-cut as a calibration standard for your other capsules. Then you can use one of your spare capsules and do the "surgery" and use it for your "remote", "production" measurement microphone.
Old 13th July 2013
Here for the gear
🎧 5 years
Thank you, that is what I'll do.
Old 7th October 2014
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🎧 5 years
Will this work with the capsule TSB160a

This capsule doesn't have FET built in. Here is a picture of this capsule:

and here is its datasheet diagram that shows impedance of 2.2k Ohm

I tried this circuit and never found it useful because my circuit gives huge noise here is a link to my circuit:

When i put it in metal box noise become less by joining the GND wire with metal box body.

Do you guys know how to fix it.
Old 21st July 2015
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🎧 5 years
Problem with 3 terminal electret

Well I found this thread that is related to what I need I am just not sure what mods to do if any to get my electret powered via phantom power. In my case I am using a Knowles 3 terminal microphone ( http://www.knowles.com/eng/content/d...-24611-000.pdf ) which I want to power off of phantom power. I am not sure how I might modify the circuit shown on the first page of this thread (with the dual 2.4 volt zener diodes) such that I can use it with a three terminal microphone. Any help would be appreciated.

Old 22nd July 2015
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Richard Crowley's Avatar
🎧 10 years
Please give us a hard URL reference to what circuit you are talking about?
I am not seeing any circuit with dual 2.4 volt zener diodes.
For that matter a great many of the images from earlier in this thread seem to be missing.
Old 22nd July 2015 | Show parent
Here for the gear
🎧 5 years
Originally Posted by Minion ➡️
Here is a simple curcuit i have used before for a electret capsule that has a low output impedance and runs of of +48v phantom power .....

This one is simpler but with a higher output impedance ....

They aren"t my designs .....

Sorry. I miss spoke. The one referenced here with the single 2.4V zener. Was thinking I would split the two lines in the + side of the mic in that circuit. The portion supplying the bias voltage I would run to the +V side of the mic and then take the output of the signal out of the mic and run it through the leg that has the 10uF cap to pin 2 of the XLR. Does this make sense? Do I still need the 1k Ohm R3, and R4.?
Old 23rd July 2015
Old 25th July 2015
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