Easy DIY amplifier for guerilla sound installation

  • I'm working on a slightly sound related project and wanted to get some insight and ideas about it. And by all means, please take my idea (that isn't new anyways) and do it on your own!

    Looking to do some guerrilla sound installations on the tops of buildings, dark alleys, empty streets. Am planning on using old MP3 players on some sort of loop, single speaker and some sort of amplifier in a weather proof enclosure. I will assume that 120V power will be available. Does anyone have any plans or know where I could get some to build just a small amplifier to power something like this:


    Would like to keep the entire project down under $20 a unit. cheaper if possible.


  • try an LM386. it's a low power audio amplifier that doesn't require many external bits to make it sing. works on 6-12 vdc, cheap, easy-to-find

    here's how to build one:


    good luck! and please keep us informed of your progress.

  • i, too, have been looking for a similar device. Anyone know of anything a little higher powered, say in the 5-10 watt range to really make a racket with some really efficient horns?

  • thanks for your input. I think I may be looking for something with a tad more umph. I really want to be able to project some somewhat ambient sounds effectively.

  • try the little gem MKII:: http://runoffgroove.com/littlegem.html

    it's the same circuit as % posted, but w/ two 386 chips run in push-pull for about 1W of power (remember that 1W is half as loud as 10W). going to a 5W amp is not going to give you a lot more volume.

    I would recommend investing in higher efficiency speakers if you're after more volume, rather than worrying about more watts. and by all means try building one of the little 386's first!! the first time i made one i was very surprised at how loud the thing was.

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  • we often use the 386 in soldering/etching workshops, it's a nice little chip.

    one thing i'd recommend is enclosing the speaker, with even a plastic cup if nothing else.

    on the other hand, get one of these:


    and take it apart. they are ridiculously loud for $20.

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  • make a class d either a kit from here or just get class d chips and build some amps from the reference design off the data sheet.