Instructables
Picture of Pre-amp to electret mic!
This circuit is very easy to do!
and all parts of it are easy to find!
It is nice to put together with design of Rtty21http://www.instructables.com/id/Easy-AM-Transmitter/
"The easy transmitter am"
so you can talk on the radio or put somewhere
hear the conversations of others!
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the parts you'll need for this project will be!
Q1 = 2N3904
R1 = 10k
R2 = 100k
R3 = 10k
C1 = 0.1μf or if you prefer 104 or 100n
C2 = 0.1μf or if you prefer 104 or 100n
MIC1 = a common electret microphone
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to put it together to design rtty21
and just put the place marked as output to next stage
pin 4 for the 555 (ne555/lm555/7555/ka555)
and ready to feed it to the same source of another circuit!
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                                                                 My First Instructables
                                                                     Yeah!!!!  XD
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                       with some debt and send a comment I will try to solve your problem!
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CameronF2 months ago

Awesome!

I attached this to my ipod amplifier, wired it to a speaker, and now peacefully listen to the outdoors from my basement.

Really good for your first instructable!

Can anyone suggest where to modify this to increase the amplification?

I am getting ~100-150mV for everything below 100dB, and at 100dB+ it rapidly rises up into the 2V range. I'd love to get some more definition in the 70-100dB range, even if I lose it in the 100+dB range.

Thanks!

I just answered my own question. To change the amplification, change the 100k resistor value. I believe doubling the resistance doubles the amplification.

hey lucas can this preamp be used for normal mobile audio
mamundsen1 year ago
This is sweet. I bought some super cheap electret mikes recently, and this is the third preamp I've tried to build. It's also the only one that works well. (I got a very nice progression from the first circuit as not working at all, to the second one working poorly and now this one working satisfactorily.
pinst2 years ago
Could someone help a newbie add a low-pass filter to this design? I have an electret mic with a frequency response of 20-20000HZ but wish to filter out frequencies above 300HZ.

Thanks!
ASCAS pinst2 years ago
make a simple audio crossover.
maixy2 years ago
awesome!
i have been wishing to make an amp
but i do not know too much the knowledge of electronic
i will appricate you if you can add some explanation to it
thx
lukas_tek (author)  maixy2 years ago
i start with eletronic like this
burn led on 220v,open light bulbs,making motors turn on with a battery
this things
framistan3 years ago
A very usefull schematic. I am printing this out on 3x5 card and will certainly use it. thanks.
lukas_tek (author)  framistan3 years ago
thanks for you !
because you see my instructables!
is this the combination for the circuit of rtty21?
lukas_tek (author)  oteng09142 years ago
May be because if you want a voice in the radio station you need a pre-amp to the mic , cause the mic alone don't make sound!
jensenr303 years ago
this looks nice.
I should try it sometime.