Introduction: LM 386 Versatile Portable Amplifier


•Soldering iron 30w
•Soldering lead
•Twizzors(optional)
•Glue gun
•QuickDry epoxy(mighty bond)
•Acrylic Flexiglass 3mm
•Acrylic Spray Paint
•Masking tape
•Electrical tape
•Transparent tube hose(option)
Or Heat shrink tube
•Philips screwdriver
•Scoring blade(for cutting flexiglass)
•Ruler(for measurement)
•Pencil 
•other tools necessary

•Parts Needed
LM 386
1*33pf Ceramic Capacitor
1* 0.047uf Metal Film Cap 50v
1* 220uf Electrolitic Cap 25v
1* 100 uf Electrolitic Cap 16v
2* 0.22 Metal Film Cap 50v
1* 10uf Electrolitic Cap
•Resistors
1* 22k 1/4w
1* 10 ohm 1/8w
2* 10k 1/8w
2* 10k Pot
1* 2k 1/8w
2* 100 ohm 1/8w
1* 330 ohm 1/8w
2* 2.2k 
1* Perf board
Wires (i used car audio wires)
Speaker Terminals
2*stereo 3.5 jack
1* Power jack (12 v)
2* volume knobs
•Housing (i used acrylic- flexiglass

Step 1: The Datasheet

Knowing the datasheet of certain component like LM 386 will help you further understand how a certain component works.Datasheet can be downloaded here:

http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/8/LM386.shtml

Step 2: Schematic Diagram

Various schematics of LM386 audio/guitar amplifier are available on many sites.,You could also found many descent LM386 ibles here.Here's the schematic found on Makezine by Rosh Hershberger.,then i manually drawn schematics on note and altered and add some components to eliminate the distortion.,Just to clarify things up,im not saying the schematics of Rosh is not perfect.,i just added some components that works for me.

Step 3: Test/Trials

In the process of testing different types of schematics gathered on various websites.
Testing my spared and salvaged capacitors.,eliminating hizz and some other sound distortions.

Step 4: Final Test / Soldering on Prep Board

Finally found the one that works for me.,all the hizz and distortion where all gone.After an hour of testing various caps,frying 2 LM386...,Yes..,i fried two LM386.,

Step 5: Putting It on a Case

Putting the amplifier board can be done in various ways,but im into using Acrylic Flexiglass,preparation on this kind of case needs more time and effort,but the result is satisfying and durable.

Step 6: Compressing the Wires

Compressing the wires and putting some insulations on bare wires using scrap oxygen hose.
•how i wired my 2 speakers @ 8 ohms 3 watts each wired in parallel.
•see image speaker wiring.

Step 7: Assembly

It's all inside the case now.

Step 8: Add Some Cosmetics

After testing the audio quality sound produced in this project.,I finallized it using black spray paint,to add some cosmetics.

Step 9: Result

After all the soldering,cutting of flexiglass,assembling it all together & finalizing it with paint.,One last thing,testing it on various audio devices i have.

•tested and runs on

•5vdc powerbank(for outdoor use)

•12 vdc power adapter charger(at home)

•2 lithium ion 18650 battery wired in series output voltage of 8.4 in full battery status-for outdoor use (improvised battery pack)


So there you have it,another DIY project that cost me $6 to build.,The sound it produced on the devices seen on iimage are superb.,Achieving what im expecting.,The base is good loud enough to enjoy music playing among friends when outdoor.,i tested it this on our last summer swimming/reunion.,Everybody enjoys it.,
Thank you for reading and hoping you enjoyed it.

Comments

author
irishjim68 (author)2015-06-25

Two of these could also be built on the same piece of perf board, using the single power supply and sending the left & right inputs to their own amp rather than putting it in mono. The additional parts would only increase the cost by a few dollars.

DSCF4379.JPG
author
anthonysugar (author)irishjim682015-08-26

Hi, I'm trying to make two bookshelf speakers using 2 Tang Band W4-656SC 4" Shielded Drivers, which require a min of 25 watts and a max of 50 watts. Would one of these chips be able to power both of these speakers?

author
irishjim68 (author)anthonysugar2015-08-27

The 386 only puts out about 450-500mW. Since your chosen speakers require a minimum of 25W, the 386 would be no good for you in that application. Something like the LM3886 power amp would be better suited for those speakers. The 3886 will put 38-50W into 8ohm load. Here is a link to the data sheet from Ti:

www.ti.com/lit/ds/symlink/lm3886.pdf

Depending on what your source is outputing, you could possibly use the 386 as a preamp.

author
rodski (author)2015-08-27

@anthonysugar
Yes it can drive it.,the sound output will vary how much volt you will supply on your amp.,Wired your speakers in parallel if you'll be using a single LM386(mono).For 2 LM386 chip(=stereo).,For better result on your project.,check LM386 Data Sheet.

15, 5:56 PM.jpg
author
rodski (author)2015-06-25

@tomatoskins
I'm having difficulty to edit this instructables,im on iphone,actually i just edited some steps that caused the change of it's title.,bug on app maybe! i'll fix it later on pc asap.

author
tomatoskins (author)2015-06-25

That a fun little amplifier circuit! Thanks for sharing! You might want to change the title of your instructable to better describe your amp.

author
rodski (author)2015-06-25

Yes,that's true.,combining two of this would be stereo in stereo.,Yet im happy with it.,Besides this is a Class AB amplifier.,I switch to my Class D amplifier 500watts 5.1 channel when i need to.Thanks for you comment.

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Bio: Electronics hobbyist and a DIYer and i love doing this stuff.
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