Mini audio amplifier with LM386

In more portable devices it use LM386 who is 1W audio power amplifier with x20 to x200 gain (26..46dB) and BASS BOOST feature.

Is very usefull to read the datasheet from Texas Instruments or UTC.

base schematic

base schematic

base schematic with bass boost

base schematic with bass boost

I made a sound surveillance system using LM386 with huge gain like in article How to get 74dB by LM386 writted by Kazuhiro Sunamura.


At LA3ZA Radio & Electronics is made a analize of this schematic with LM386, see the document.

At Decibels (dB) Calculator page you can understund the conversion between gain using dB, e.g. 74dB = x5000 and 20dB = x10.

I design a schematic who use jumpers for classic and special gain:

niq_ro's design

niq_ro’s design

The cases are:

  • with all jumpers free, gaine x20:


  • close 1-2, gain x20..x200:


  • close 2-3, gain x50..x5000:


For unidirectional intercom schematic is:

A version a board and montage can be:




You may also like...

11 Responses

  1. It’s actually a cool and helpful piece of info. I am satisfied that you just shared this useful info with us. Please keep us informed like this. Thank you for sharing.

  2. I’d always desire to be updated on new articles on this web site, saved them to my favorites!

  3. Awesome write-up. I’m a normal visitor of your site and appreciate you taking the time to maintain the nice site. I will be a frequent visitor for a long time.

  4. That is a very good tip particularly to those new to the blogosphere.
    Brief but very accurate information… Many thanks for sharing this one.
    A must read article!

  5. 97Ute says:

    I must say you have high quality articles here. Your page can go
    viral. You need initial boost only.

  6. AmandaTor says:

    Hello, you used to write magnificent, but the last several posts have been kinda boring… I miss your great writings. Past few posts are just a little bit out of track! come on!

  7. Good job says:

    Good post, keep

  8. taruhan bola says:

    I’m absolutely keen of reading posts for the subject of setting up up new website online, or maybe even concerning Lookup engine

  9. Sienna says:

    Hello , I do believe this is a fantastic blog.

    I stumbled upon it on Yahoo , I’ll come back once again.

  10. Tammara says:

    Greetings! Really helpful advice on this post! It really is the small changes that make the largest changes.
    Thanks a lot for sharing!

  11. Kimberly says:

    The article has actually peaks my interest. I’m going to bookmark your site and
    keep checking for new info.

Leave a Reply

Your email address will not be published. Required fields are marked *