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Picture of DIY mini Guitar Amplifier
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In this instructables I'm gonna share the process by which i developed my small guitar amplifier (actually i'm not a guitar player, but I called this project like this because of the appearance of the mini amplifier, so it can be used as a general purpose amplifier as well).

My main intentions were to keep it as small as possible without sacrificing the sound quality, to make it looks like vintage and to turn it into practical and affordable. So some features couldn't be included in it, as sound distortion for example.

This project requires little electronics skills, since the amplifier circuit is pretty simple (thanks LM386), and a bit of wood working skills, since the box isn't that complex at all. I'll give the measures I used in the case of my amplifier, but actually it's up to you, since the design isn't the most important aspect of this project.

So here goes the list of components I used for the electronic part:

  • 1 LM386
  • 1 resistor of 10kOhms
  • 1 resistor of 10Ohms
  • 1 electrolytic capacitor of 220uF/16V
  • 1 ceramic/polyester capacitor of 33nF
  • 1 ceramic/polyester capacitor of 47nF
  • 1 potentiometer of 10kOhms, if possible with switch
  • 1 jack plug(P10)
  • a 2´1/2 speaker - 4Ohms
  • a 9V battery plus connector or a 7.4V lithium battery

The most expensive component is the speaker, and I used a Sony one, but it´s not necessary to do so, I just chose this one because there are few options of 2´1/2 speakers to buy, and because the sound quality of this speaker is simply amazing, but any brand of speakers is fine since it fits the project.

Step 1: The case

Picture of The case
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The case is pretty simple, and can be done with plywood or any other kind of wood. I used some pieces of wood I had at home, I don't know what kind of wood it is, but it's not important at all.

I used some screws and wood glue in order to unite all the parts of the box, but maybe just the wood glue is enough, I would just recommend the use of screws in the bottom of the box, because then it's possible to take the speaker out of the box easily.

As a suggestion the box can be covered with those fabrics that are used in common amplifiers, or maybe painted with some kind of varnish.

The measures are specified in the PDF file (on the bottom of the page), some measures can be different according to the speaker or maybe the kind of wood you are using, then just make sure to fit them to the materials you are got.

It's not necessary to use the same materials and components that I'm using, so some characteristics can be a bit different. what I mean is that you don't need to buy new materials since you already have some that can fit the project pretty well.

Because I also did this, I just grabbed some stuff I had at home, put everything together and then the Mini Amplifier was born.

tsamarakoon2 months ago
Can I use a 6Ohm speaker instead of the impedance specified?
Brucela9 months ago
Looks good. I think you will need a preamp section for electric guitar amplification. The LM386 alone will not work well for the magnetic pickups on the guitar.
ArthCrafts (author)  Brucela9 months ago
Thanks. Yes, you are right, the gain of the circuit isn't enough to amplify the signal of a guitar, I'm actually thinking of upgrading this amplifier as long as I've learnt lots of new stuff since I posted it.

Hi, first of all thanks a lot for the post. I am a beginner and struggling to put it to work can you please provide the wiring diagram as I am using breadboard. Thanks!

ArthCrafts (author)  PrasenjitD71 year ago

Hi, thanks for your reply

I did the circuit of the picture below, but there are other suggestions in the datasheet of the LM386, provided by the fabricator of this component, maybe they can fit better your purposes, you can find the datasheet in the link below:

http://www.ti.com/lit/ds/symlink/lm386.pdf

bassboost.png
BigCthulhu1 year ago
Sorry, the joke of my lousy android tap screen... correctly: "more flexible" and "may be connected".
BigCthulhu1 year ago
Nice idea, and congrats. I've just finished an lm386 project, (not the first, in every year I build some...) and this ic is my favourite when building easy but good sound amps for indoor using. I'm a guitarist, and I can claim this amp in its state is perfect for guitarists as a practising indoor equipment. My mentioned project above was just a guitar amp, it's tried, works well. Just a tip to use it morelexible: the pin 8 and 1 may beconnected with a linear pot (5 kohm) to set the gain for other sources.
Have a nice day!
Fhtang!
kipgendio2 years ago

Shouldve done a guitar test... and it wouldve been great if you had included a built in distortion.. anyway it was simple and sounded nice

ArthCrafts (author)  kipgendio2 years ago

Thank you for your reply, I haven't done a guitar test because I'm not actually a guitar player, I don't even have a guitar, but as a future upgrade, I'm planning on adding bluetooth communication and a USB charger for the bateries, a built- in distortion could be nice as well