"Phantom power 4 mic. "

[dacflyer]

i have a small portable amp ( 1 watt ) use for various things,, it works great on dynamic mic.s
but it will not work a electric mic, someone told me they need power to make them work,, but these electric mic.s only have 2 leads,,
i need a schematic of sorts to make a small adapter that i can plug inbetween the amp and electric mic..anyone got a idea? i was told also that the adapter could power most any mic too dynamic mics too.. thanx for feedback..no pun !

[viveguy]

It sounds like you are using what is known as an 'electret'microphone capsule.If so,there is a JFET in there that needs to be biased.You can do this by applying 1.5 to 5 volts dc to the high side lead,the other lead being (-) or ground.You should also put a series resistor in for current limiting say around 2.2K or higher.The other thing you need to do is ac couple the output with a capacitor of about .22uF or higher,depending on your low frequency response needs.
You can get more info and schematics at epaorama.net,Digikey or,planetee.com.PlanetEE is the online service for Electronic Design magazine.Look in the archive of the "Ideas for design".This is a monthly competition they run for simple or alternative circuit ideas.<p>Regards,
AL

[Externet]

Hello Dacflyer.<p>The electret condenser microphones take a little power via the same lead the audio exits. Isolating the audio and power is done with a capacitor and a resistor.
Here is a great place to dig deeper :<p>http://www.hut.fi/Misc/Electronics/circ ... ering.html<p>Miguel

[dacflyer]

thanx guys..