Electret microphone into iMac 3.5mm TRRS headphone jack amplification

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I have this electret microphone: http://www.farnell.com/datasheets/1505849.pdf

And I've put it onto a 3.5mm TRRS (4 pole) jack to go into the iMac headphone jack. For the iMac to recognise/accept the mic it needs to be wired with a 10k resistor in parallel and speakers must be 'faked' bz using 33ohm resistors for left/right lines.

It works well but the signal is weak. How can I amplify the signal just a little bit? This is a dirty prototype project and it's not about quality but just about the concept so the easier/quicker/the less parts involved, the better.

I think there is 2V coming out of the headphone jack for the mic but I'm not sure. Is it possible to amplify the mic without using an external battery/energy source?

I tried this circuit but there was just no signal anymore?

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Thanks

Best Answer

That particular electret has a pretty low sensitivity. You might simplify your life by using a mic with a higher sensitivity, or better yet, one with adjustable gain built in. This mic from Knowles has adjustable gain. This app note has a pretty good explanation of how to convert a three wire mic into a 2 wire mic (with Vdd and data sharing the same line).

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