Re: Microphone (3.5mm plug) to an ADC (phono interface)

On 14 Nov 2005 15:16:02 -0800, "binodbista@xxxxxxxxx"
<binodbista@xxxxxxxxx> wrote:

>Basically I want to connect a microphone which has a 3.5mm end and
>connect this into a phono input.
>
>I was told I need to do something in between as it's a microphone input
>and it is not as simple as just using a 3.5mmm to phono converter

A phono input applies some frequency corrections, known as RIAA
correction. Basically, a phono input boosts low frequencies while
dimming high tones.
Apart from that correction, 'phono input' does not fully
describe the type of input. It can be meant for anything from
crystal to MD to moving coil.

Also important to know is the type of microphone involved. Most
low-cost microphones are elektret nowadays. Which means, that
they output a voltage that is OK for a crystal type input but is
far to high for any other phono input.
Elektret also requires either some powersupply (not available on
a phono input) or a high impedance input (available if the phono
input is suitable for crystal; but most aren't.)

If your microphone is of the 'dynamic' type, the voltage levels
won't cause any problem if the phono input is meant for MD. (Most
are.)

All by all: using a phono input to amplify a microphone is not
the easiest way to go :-)

--
Kind regards,
Gerard Bok
.