Portable Guitar Amp With Distortion / Bass Amplifier - 9v / LM386 IC

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Introduction: Portable Guitar Amp With Distortion / Bass Amplifier - 9v / LM386 IC

About: I am a musician, internet developer, and a hobbyist pedal builder.

 This is a really simple portable guitar amp project you can complete in an afternoon ; with the parts you need at hand.  I used an old surround sound speaker as my enclosure, and used the speaker.  The unit also has 5 tone settings to allow you to go from clean to gritty. 

NOTE:  if you are thinking about building one of these, see my newest addition first based on the 'Little Gem' amplifier, using a few more parts. It sounds much better.

https://www.instructables.com/id/The-Little-Gem-Mini-Amplifier-Guitar-Amp-/

Step 1: Parts List / Wiring Diagram

The diagram below explains this build in detail.  If you want 5-mode distortion, then you simply use the dip switch in place of the SPST switch on the 2.2uf-10uF capacitor. Remember that the speaker you use will make all of the difference in how clean your new portable guitar amp sounds. Mine sounds pretty clean, I achieve this by isolating jacks and components from each other, and I hot glue the audio lines and PCB wiring to avoid leakage. 


Parts List:

Enclosure: I used an old surround sound speaker as my enclosure. You could make this unit into a box and use as a 'head' for speakers in mini-cabinets too. 

9V Battery
9V Battery Clip 
Input / Output Jacks 1/4 Mono 
SPST Switch OR Dip Switch w/ 5 settings
PCB / Board material 

LM386N IC 
8 Pin IC socket (optional)
4.7uF Capacitor
10uF Capacitor
100uF Capacitor
470uF Capacitor

[optional - for multiple distortion modes]

0.01 capacitor
2.2 uF capacitor
00.47 capacitor
4.7uF capacitor
10uF capacitor 

+ higher cap values = heavier distortion

 

Step 2: Putting It Together ...

This is a pretty simple PCB for making it all work - I think the power output is a 1/2 a watt.  Follow my wiring diagram (photo 2) to put it all together.

Some notes:

 I make a daughter board for my dip switch and extra capacitors for my multiple distortion modes.

 I usually use shielded audio cable for the inputs and outputs to cut down on any feedback / buzz ; and a socket for the LM386 IC (not necessary) - just in case it gets toasted.  

The LED for on/off is out the front [ use a 470ohm resistor between +9 and your on off switch ] 

 Battery location could be internal, but they get ate so I mounted mine externally. A 'Supercap' battery is another idea -- (DIY 9v rechargeable) or some other rechargeable battery as this device runs up to 15v. 

Dip switch could be replaced with a 6-position selection switch / or other

Gain / Volume POTs could be added 





Step 3: Finishing Up

You can build this into anything, but I decided an old surround sound speaker enclosure would work best (for being dropped, etc..).

I'll probably add these in the near future:

Volume / Tone Pots 
A distortion unit clone on a foot switch (VOX tone bender clone)
Rechargeable Battery (of some kind) & built in charger / car charger
6-way tone selection switch
More stickers
A handle 
PCB mounts



2 People Made This Project!

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user

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Tips

Questions

71 Comments

How long does it last with the 9V battery?

Where to connect the LED?

Could a speaker be put on the output instead of a jack to output the sound?

1 reply

yes, but only use a small speaker

Is it possible to use ceramic caps instead of electrolytic

user

What's the role of the C2, C3 and C4 capacitors?

1 reply

C4 filters input audio signals and C2 filters output signals. And C3 filters the Vcc coming from battery.

Great tut, but why use a switch between pins 1 and 8???
A pot works much better and provides more tonal flavors.
For added distortion, use clipping diodes. These can be strategically inserted and still use the switch to give different clipping options. Also, a simple tone stack works great in the Little Gem. You new guys should start with the BMP stack...then move up to the 3-Knob versions ;)

how do i know where i can put capicators - and + because it isn't clear for me,

1 reply

Look at the schematic.
If you can't read schematics--go to runoffgroove dot com for the perfboard layout.

how many voltage in the capacitor of 4.7uF Capacitor, 10uF Capacitor , 100uF Capacitor, and 470uF Capacitor. Please reply ... tnx !

1 reply

Anything above the rated piwer source. I typically use 35 or 50v caps.

OK so I completed the circuit .. Everything works great. But I dont know why but the amp cant pick the B string on my guitar . Is it because of the pickup or something else ?? FYI This is my first guitar effects project.

1 reply

It's your guitar. If the amp is putting out a signal on all other strings--the amp is fine.

Great 'ible. Built one, and it wasn't working well enough with a piezo pickup. Found I could use a MPF102 as a buffer, and if you replace your switch on the 10uf cap with a 1-2k resistor, you can have variable gain!

Hi! That's a great job you got there.

Now, I'm planning to build the amp, but I'm having a hard time figuring out how I could add a volume pot... Can you please enlighten me?

Thanks

1 reply

you can put a few 5k potentiometer, to connect you have to look at it from the front and pin 1 is ground, pin 2 goes to the output of the circuit, and pin 3 to jack TIP

the polarity of the capacitors is it right negative?