Re: Knowles miniature microphones and standard mic inputs

[Steve Beet <steve.beet@xxxxxxxx>]

Hi Pawel,

You could adapt the circuit from this web page:

http://thedatastream.4hv.org/prm_mic_preamp.htm

However, there are two factors which you would need to consider before modifying the circuit for your own purposes. One is the fact that your chosen mic capsules are 3-terminal devices (separate power and signal connections, where this circuit uses 2-terminal devices) and the other is the output impedance (4400 ohms, nominal, which is a bit high to drive a pro XLR input directly, which is why you really need some amplification in the circuit).

You also need to be careful about nomenclature. Some manufacturers have been known to use the term "phantom power" wrongly:

http://www.uneeda-audio.com/phantom/phan.htm

Good luck!

Steve



On Wed, 8 Aug 2012 10:56:37 -0400
PaweÅ KuÅmierek <pawel.kusmierek@xxxxxxxxx> wrote:

> Dear list,
> 
> I want to use Knowles miniature microphones (e.g.,
> http://www.knowles.com/search/prods_pdf/FG-23329-C05.pdf).  I want to
> record the audio signal into a recorder or sound card that has typical pro
> XLR mic inputs, and I would also like to use the 48V Phantom Power
> available from such input to power the microphone. Any one has a schematic
> of a circuit that would allow to do this without frying the mics or the
> recorder?
> 
> Thanks for any pointers,
> 
> 
> Pawel