improve telephone microphone circuit for amplifying fiddle

Your mic is *not* sensitive if you have to be right on top of it to get sound. You need more gain or a better mic so you can be a reasonable distance from it - a foot or two. That way, a few inches one way or the other wont make for a huge difference in level.

Luhan

I don't know much about this, but I am wondering if this is the purpose of an automatic gain controller (AGC). I have seen some transistor amplifiers that use FETs as voltage-controlled resistors to automatically adjust the gain.

Do you people think this is suitable for this problem?

Hey Luhan,

thanks for the advice. But, the whole point is trying to get _this_ mic to work, and it's a telephone mic so I think it's designed to work best up close. I'm not sure how more gain could help me because that would be a linear increase, right?

Cheers,

Ben

Yes - start over and use an electret mike. Unless there is some reason you want the mike to be carbon?

Here are 4 sites of interest. The first one discusses powering an electret mike; the second provides a kit with an amplifier; the third discusses using en electret to amplify an acoustic guitar and the last provides a simple pre-amp in case your amplifier requires it.

Ed

Thanks for the advice but read my original post and you'll see why I need to use this mic. I specifically need to modify the circuit described in that thread to change the response.

Cheers,

Ben

Ok, Ben. Call me dumb as a stump, but I can't find anything that tells me why you need to use the particular mike.

But since you are sure you want to use it, try this adition to the circuit Rich gave you:

Batt(+)---+------+ +------+------+ | | | | | P | | P | O