Instructables
Hey everyone.

So here's how this project came about.  I needed  two, 2 watt amps for a speaker project, and didn't want to go buy amplifyed computer speakers and rip the amp out like i see some people doing, so i decided to buid one.  Well i googled a little, and came up with a circuit for the LM380 IC.  It seemed to be a pretty popular circuit, posted on a lot of different websites, so i figured i would have a lot of support information if something went bad. well i guess i fail at google but thankfully a helpful user helped me out. c181155 helped me out, and posted a link to the datasheet which helps alot*stupid me didn't even bother to look at the datasheet...* heres the link
http://www.national.com/mpf/LM/LM380.html#Documents
 So in this instructable I will walk you through the building of this amp and the things that i found confusing.

*Alot of the actual instructions are within the pictures, as i found it easier to explain this way.

Step 1: Materials/Tools

Picture of Materials/Tools
Materials
------------
Paper and glue
some copper strands for jumper wire

an LM380 IC
2- 25V(or higher) 470uf electrolitic capacitors
a 2.2 ohm resistor
a 10k audio taper potentiometer
a headhone jack/rca jacks/you get the point
a power supply(10-22V)

Tools
--------
soldering iron
probably some pliers
a multimeter if you have one, however you can definately make this with out one
a needle (sewing, not epidermic...)
some aligator clips will probably be very helpful, i know they were for me
 
Remove these adsRemove these ads by Signing Up
So, just to confirm, the positive input goes to the potentiometer and the negative input goes right to ground?
yes!
tealk1 year ago
Can i use 9v? i want to make some portable speaker for my bike, i wanted to built it with lm386 but its only 1.5 w, and this one is 2w
nickmccullough (author)  tealk1 year ago
Yes! although it will be less powerful. The datasheet states that 10V is the minimum, however i just tried a 9V battery, and it plays fine. If i were you though, i would put 2 9V's in series, just because id rather my music be louder:D

http://www.ti.com/lit/ds/symlink/lm380.pdf
thanks, i as i said i wanted to build some speaker system so where ever i go i could listen to loud music, lm386 is almost same price like lm380, but it have more parts, less power,.....thanks, i will try out this one, first with 9v, but then i will use 2 9v or 9v and 2x1.5v,.....i will post test in next month
nickmccullough (author)  tealk1 year ago
unless you are driving some pretty efficient speakers, 2-3W wont be all that loud, just a warning. Also, you can get free samples at the TI website:) there is an Instructable somewhere for that
Could you post video of music playing this speakers with amp?
nickmccullough (author)  tealk1 year ago
i don't have anything to record a video that will be decent enough audio to hear it:/
:( ok, thank you .
schumi232 years ago
This is an amazing instructable,thanks for posting it !
Ive been looking around a lot for a good amplifier (IE: Not lfm386-n) however, if you search amplifier, you only get those with lm38g-n(or rather all others are swamped out).
Also, great idea with the paper/glue! (though since i am a beginner mostly, i will still buy the board.
Also,just curious, how good sound quality are you getting from it?
nickmccullough (author)  schumi231 year ago
sorry, i didn't get a notification that i got a comment, and just saw that i didn't reply to one today... The quality is good enough for me, theres a lot of chips that will do a ton better though. There is more hum and its a lot more sensitive to things like a light being plugged into the same outlet than other amps I've build are
nickmccullough (author)  schumi232 years ago
thank you! I too was frustrated with the surplus of lm386 amps(no saying they are bad instructables, just hard to find other amps)

thank you, hope everything goes well!
jwatte2 years ago
One warning: Paper is a lot more combustible than FR-4 fiberboard used in a regular circuit board. The three middle pins on each side of this circuit are "heat sink ground" -- they are supposed to be routed to a large area of copper on the circuit board, to dissipate heat.

If you play this circuit at its full power, those pins will become very hot. If you're lucky, the circuit will go into thermal overload protection. If not, your improvised "circuit board" will scorch and maybe even catch fire!
nickmccullough (author)  jwatte1 year ago
thank you for your concerns. I took that into consideration when building the circuit, and tested it for long periods of time at all power levels (including full power) and the pins became warm, however perfectly fine to hold your fingers to them.
I also tested it in a very small, confined box with no problems to date.

Again thanks for the concerns and advice
Here is the link to the application sheet & more , http://www.national.com/mpf/LM/LM380.html#Documents
It also has a big brother the 384 & a low voltage version the 386. Happy Hackin'
nickmccullough (author)  Lectric Wizard2 years ago
thanks a lot, will include the link in the instructable and give you some credit
Love the paper & glue idea ... way to think "outside the box" This is a great chip for audio use. I gone thru 100s in my work. Made everything from distribution amps for broadcasting to home built stereos by "bridging" two. There is a great application sheet online. Good Work !! Cheers!
nickmccullough (author)  Lectric Wizard2 years ago
thank you sir, i may play around with bridging the two together before i finish my speaker project and mount the amps inside
twturley472 years ago
This is what I love most about the talented, creative people on Instructibles.
No pref board? No problem, I got paper and glue! And look it works! Great project! Good pic’s . Good layout. Thanks for sharing.
nickmccullough (author)  twturley472 years ago
Thank you so much! It means alot