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

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

 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

Picture of 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 ...

Picture of 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

Picture of 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



Comments

RafaelM (author)2017-08-13

How long does it last with the 9V battery?

FreddyR16 (author)2017-02-09

Where to connect the LED?

Erik-Mattson made it! (author)2016-11-28

Made it (breadboard). And it's a pretty cool little amp for sittin' and jamming. Added a genuine on/off switch, volume knob, and power indicator LED. \m/

egyedia (author)Erik-Mattson2016-11-29

I like the extras you added to this amp!

I am planning to build this together with my son for his mini guitar. I am not a total newbie, but I am not a hardcore circuit builder neither. Could you just indicate where your additions should be mounted?

I am also thinking about adding the support for dual power (battery vs external power supply). A headphone output (which would switch off the speaker) will be nice as well :)

Do you have any suggestions regarding these?

Thank you.

hfresco (author)2016-02-10

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

owatson (author)hfresco2016-07-26

yes, but only use a small speaker

MehmetÖ2 made it! (author)2016-06-10

thank you. i did this circuit and it works well :=)

Jonko123 (author)2016-05-12

Is it possible to use ceramic caps instead of electrolytic

Guii (author)2014-05-12

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

samtechpro (author)Guii2014-12-19

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

avianoguitarist (author)2014-02-13

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 ;)

djurenas (author)2013-05-13

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

avianoguitarist (author)djurenas2014-02-13

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

cholo123 (author)2013-05-16

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

avianoguitarist (author)cholo1232014-02-13

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

pmakakatok (author)2013-08-18

how to add volume, bass and treble control?

You build and add a tone stack.

blinkme (author)2013-10-22

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.

avianoguitarist (author)blinkme2014-02-13

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

jsawyer (author)2013-08-29

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!

NunoMorna (author)2012-12-18

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

pogodike200!!! (author)NunoMorna2013-01-18

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

pogodike200!!! (author)2013-01-18

the polarity of the capacitors is it right negative?

ghosty37 (author)2012-01-14

Hy, I made it to. It works very well. Thanks.
I replace your dip switch by a rotary switch.

I add volume pot(100k lin.), like in another project I did at the same time.
https://www.instructables.com/id/Distortion-Pedal-With-Stutter-Effect/

What type of speaker did you use?

jorence (author)2011-12-22

wat r the voltages of the caps??

bgondes (author)2011-11-09

how to make the sound distortion is long?????

volney (author)2011-07-05

Great instructable! But how do i connect an on/off switch and LED?

jimdkc (author)volney2011-08-15

This circuit needs no on/off switch. The way the input jack is wired, the ground circuit to the battery is completed when you plug in your guitar. The sleeve of the plug shorts the ring and sleeve connections on the jack. (The input jack is actually a stereo jack, not mono.)

You could put an LED from the + battery terminal, through a current limiting resistor, to ground.

andrezfen (author)2011-07-31

i followed your circuit and it is successful. than you capthook :D

coolguy2015 (author)2011-04-12

for volume control how much k ohms of pot should i use?? reply me plzzz....

capth00k (author)coolguy20152011-04-13

I would suggest building my other model (the little gem) mini guitar amp, as it sounds much better to my ear. Try using a 50K A (audio) PoT on your build.

Peace

Capt.

Thereyouhaveit (author)2011-03-15

I completed building it , as a preamp , it sounds so soft when i put it into my power amp :(

as a guitar amp for a passive strat .

Thereyouhaveit (author)2011-03-03

Hey , can i use this as a pre amp ?

theVader75 (author)2011-03-02

can I use MC1458CP1 or OP270GP for this application?

coolguy2015 (author)2011-02-06

my input is mono, how can i connect it??

Teburon (author)coolguy20152011-02-18

i'm wondering too. how did you solve this? just connect all the grounds together?

coolguy2015 (author)Teburon2011-02-18

yes, i did connect all the grounds and the sleeve of the jack together.

coolguy2015 (author)2011-02-08

Its working but when i turn the switch, there is no distortion except clean sound.. plzz any one help me......

Teburon (author)coolguy20152011-02-18

did u use 10uF capacitor for the dirty sound? if you only used Switch -> .01uF -> LM386 then you'll only get clean sound

coolguy2015 (author)Teburon2011-02-18

I've used 10uF capacitor

coolguy2015 (author)2011-01-19

dude i have a 6 volts DC adapter, can i use it instead of 9v??

brainstromer (author)2010-12-29

hi there
i have some question
di ineed to use spesifik capasitor
like mylar or elco??
because on my country not all tipe capasitor avalaible
and i don't see "spesific type" on your diagram

sorry for my bad english
thanks bro..

warfighter (author)brainstromer2011-01-03

can u pls tell me if it is electrolitic (elco) or normal capacitor
thnx

capth00k (author)warfighter2011-01-03

Normal Radial / Axial capacitors.

capth00k (author)brainstromer2011-01-03

Just use Radials. Sometimes I use axials. The best 'tone' capacitors are Paper in Oil however. Find those, and you're golden.

dan95 (author)2010-12-10

where do i plug the distortion dip switch

capth00k (author)dan952010-12-11

Where the 2.2 uf - 10 uf capacitor is after the 'clean / distortion' switch. To do the 5 tone dip switch just bride one side of the switch as 'negative', and wire em up as shown off the dip switch. If you have more than one on, remember you will be adding (2.2uf + 1 uf = 3.2 uf, etc.) to make unique distortion tones.

Additionally, you can use a rotary switch to do the same thing without having to fuss with a dip switch (cheaper) ; a 12 position rotary switch is perfect for it.

WALLz (author)2010-11-09

Powersome! \o/

Falcore (author)2010-04-12

It sounds AWESOME!!! I had a similar amplifier with LM386 but I decided to try this as a portable amp for my phone and it has great power and quality...

About This Instructable

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Bio: I am a musician, internet developer, and a hobbyist pedal builder.
More by capth00k:Fixing an iMac g5 Power Supply using an ATX (pc) PSUThe ' Little Gem ' - Mini Amplifier / Guitar Amp -Portable Guitar Amp with distortion / Bass Amplifier - 9v / LM386 IC
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