simple mic amp

[boabynixon]

Hey guys i am a new poster but have been reading most of the posts since i began college 2 years ago and have enjoyed all the knowledge that this fine community has to offer also used some ideas for my final project (Weather station) which i passed 8) thx guys

now here is my little project for halloween, as i have purchased a "deluxe clone trooper" costume. i would like to modify the helmet with a small voice amp consisting of a small microphone, amp circuit (LM386 prefferably) and output it to an 8ohm speaker.

1. Do i need any pre-amp circuitry for the mic before main amp stage?

2. if i do, do you have any suggestions?

3. would the simple "typical applications" on the datasheet be suitable for main amp stage? ie **broken link removed**

at a later stage once ive got my bearings with the design and circuit principles etc i may modify for the static burst at end of the message.

sorry if these seem like dumb questions but i have alot of theory and no clue how to put it into practice instead of being an "armchair engineer" again if you have any ideas or suggestions please write a post, and again great community.

 

[boabynixon]

would this schematic be any good for my needs, i dont want to deafen people, just be heard


https://circuitos.tripod.cl/schem/r5.gif (it would be good if they had the cap values, im thinking uF , any audio friendly peeps here?)

again i would like to use the lm386 if possible as components arnt the cheapest around my area. i will try breadboarding the schematic an let yall know how i get on but its 5am and im hitting the hay, but plz any suggestions will be greatly appreciated.

 

[Electrix]

here's a low cost solution

 

[audioguru]

If the microphone can hear the speaker then you will have acoustical feedback howling. Turn down the mic preamp's gain, turn down the speaker volume, eat the mic and scream into the mic, then there won't be howling.
You could mount the mic and speaker at a fixed distance between them and fiddle with adding some out-of-phase speaker signal to the mic input to try and cancel some feedback but it will sound strange.