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Can someone help me with a simple audio amplifier? Answered

I need to build a simple audio amplifier for an mp3 device for my A levels, but i dont know which amplifier to use, i would like the amplifier to have a variable gain of zero to the maximum and i also have 2 0.5 watt 8 ohm speakers. I was going to use the simple amp from here, but i am not sure if i can get the full 1 watt from the speakers using that amplifier. Any help will be appreciated.

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Quercus austrina (author)2011-03-06

The LM386 is one of the easiest amps to work with. It will work with a fairly wide range of voltages and it can be modded to be much more than a basic amp. While not particularly powerful, it can be quite nice for small rooms and personal listening. It is also one of the easiest to "cut your teeth" on. It is also a fairly good match, powerwise, to your speakers.

The best thing you can do is use the datasheet that NachoMahma linked to. Start with the basic circuit and experiment with some of the mods they show. I have a LM386 2.1 system design I did for another 'ibler that gives the basic layout with options and pin connections. I really ought to put it up as an 'ible. I can send it to you if you would like.  

Qa

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user

Hello Quercus austrina here it is 4 years later and I would really like to see your LM386 2.1 system design I did for another 'ible. Yes I know that's asking quite a bit after a 4 year gap but what can I say, I'm optimistic!

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orksecurity (author)2011-03-06

Lots of designs on the Internet.

Lots of designs in books -- my standard recommendation is Jung's IC Op Amp Cookbook, which really does have an op-amp circuit for just about every task, with detailed discussion of the issues in its design and what you might or might not want to alter.

Part of passing this test is demonstrating that you know how to do your own research...

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COOL_Q (author)orksecurity2011-03-06

i have been doing my own research, and i have found a few amps i could use, however i havnt found any suitable ones that have a variable voltage gain.

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steveastrouk (author)COOL_Q2011-03-06

That's why you put a volume pot on the input !!

Steve

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NachoMahma (author)2011-03-06

. The LM386 is only rated for between 1/4 and 1/3 W. You're not going to get 1 W out of it without some serious heat removal.
.  All the circuits at your link are mono only. You will need two for stereo.

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COOL_Q (author)NachoMahma2011-03-06

i got 2 LM386N-3 ic's and they are rated at 500mW each, and i was thinking of using 2 of those circuits but i dont quite know of how to connect them from mono to stereo.

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orksecurity (author)COOL_Q2011-03-06

Stereo is just two mono amps next to each other.

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