Instructables

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.

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

 
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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

 
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Guii7 months ago

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

samtechpro Guii20 hours ago

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 ;)
djurenas1 year ago
how do i know where i can put capicators - and + because it isn't clear for me,
Look at the schematic.
If you can't read schematics--go to runoffgroove dot com for the perfboard layout.
cholo1231 year ago
how many voltage in the capacitor of 4.7uF Capacitor, 10uF Capacitor , 100uF Capacitor, and 470uF Capacitor. Please reply ... tnx !
Anything above the rated piwer source. I typically use 35 or 50v caps.
pmakakatok1 year ago
how to add volume, bass and treble control?
You build and add a tone stack.
blinkme1 year ago
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.
It's your guitar. If the amp is putting out a signal on all other strings--the amp is fine.
jsawyer1 year ago
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!
NunoMorna2 years ago
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
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?
ghosty372 years ago
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.
http://www.instructables.com/id/Distortion-Pedal-With-Stutter-Effect/

What type of speaker did you use?
Mini guitar amp large.jpgMini guitar amp pcb.jpg
jorence3 years ago
wat r the voltages of the caps??
bgondes3 years ago
how to make the sound distortion is long?????
volney3 years ago
Great instructable! But how do i connect an on/off switch and LED?
jimdkc volney3 years ago
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.

andrezfen3 years ago
i followed your circuit and it is successful. than you capthook :D
coolguy20153 years ago
for volume control how much k ohms of pot should i use?? reply me plzzz....
capth00k (author)  coolguy20153 years ago
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.
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 .
Hey , can i use this as a pre amp ?
can I use MC1458CP1 or OP270GP for this application?
coolguy20153 years ago
my input is mono, how can i connect it??
i'm wondering too. how did you solve this? just connect all the grounds together?
yes, i did connect all the grounds and the sleeve of the jack together.
coolguy20153 years ago
Its working but when i turn the switch, there is no distortion except clean sound.. plzz any one help me......
did u use 10uF capacitor for the dirty sound? if you only used Switch -> .01uF -> LM386 then you'll only get clean sound
I've used 10uF capacitor
coolguy20153 years ago
dude i have a 6 volts DC adapter, can i use it instead of 9v??
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..
can u pls tell me if it is electrolitic (elco) or normal capacitor
thnx
capth00k (author)  warfighter3 years ago
Normal Radial / Axial capacitors.
unnamed.jpg
capth00k (author)  brainstromer3 years ago
Just use Radials. Sometimes I use axials. The best 'tone' capacitors are Paper in Oil however. Find those, and you're golden.
dan954 years ago
where do i plug the distortion dip switch
capth00k (author)  dan954 years ago
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.

varitone2.jpg
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