Rechargable pocket sized amplifier

In this instructable I gonna try to describe how to make a simple rechargable pocket sized amplifier.
It's works using only two low power transistors and two nickel metal hydride batteries (Ni / MH).
The case is made with 3mm cardboard for making it as light as posible.
Ps: I'm from Argentina so let me know for any grammar mistake

Step 1: Materials

For the case:
A piece of 3mm cardboard
A cutter
Some glue
Screws
Separators

For the circuit:
R1= 4k7 resisor ( yellow violet red)
R2= 1M resistor (brown black green)
Q1= BC548 or 2N3904
Q2=BC327 or 2N3906
C1= 10uF capacitor
2 AAA batteries

Extras:
A batteries charger
A wire for connecting the amplifier to the sound source
A wire for connecting the amplifier to its charger

Comments

[tealk]

i make this amp, but using bc547 and bc557, bc 547 is good but 557 geted to hot,...
i ll try to make one with your transistor, for now its working but not as yours, i lll use your components and see next

[Crontox102098]

Bruno, podría usar dos de estos en unos audifonos? compré unos audifonos chinos y querría meterle dos circuitos de entros internamente.. podría? los Speakers son de 32 - 35 Ohm según el multimetro

[jhao sebastian]

Hi, i am unfamiliar with electronics so i have some enquires. Which connections are joined to the "IN" section? The left, right or ground of the input jack?

[Jimmacle]

I have a question about the amp circuit. I was goofing around with it, and I noticed nothing different when I removed the 1M resistor. What is that resistor supposed to do?

[Jimmacle]

Also, where would I put a volume control resistor in this circuit?

[lukeD]

great ible *5

Can I hook up 5 big speakers to this amplifier?

[agm88]

in paralel probably

[4lifenerdfighter]

That's like getting a dog and asking if it can pull 5 plows.

[iApple guy]

the sound from mine is just a buzzing sound

[rocketshubham]

i have made this and getting high distortion noise .....where have i did wrong ?
instead 3V i m using 9V battery and transistor BC328 in place of 327 , else everything is same .

[M0HIZ]

You should try using two AA or AAA batteries as suggested, because you are probably over-driving the transistors.

[Kante Tech]

You should put the volume on the device on low and make sure all the input connects are wired strong and not touching.

[rocketshubham]

all inputs are tight and i m not getting enough sound in low volume ...and high distortion at high volume .

[Kante Tech]

If this is the case then either your speakers are in bad shape like my first pair or your battery is low on power so its not supply much of a voltage. If you don't mind can you try to post a picture of the speakers. If nothing else it must probably be the transistor that's the distortion.

[David97]

If I up the size of the transistors can I drive 4ohm speekers?

[Begradoo]

I built this little amp and it works great considering its simplicity and low voltage. It drives cell phone speakers especially well.
Would it be possible to use a more robust set of transistors and higher uf caps and increase the voltage? Maybe drive a little bigger of a speaker.

[mamajr96]

How exactly do you make the PCB, understand you need to print the PDF, but what exactly do you do.

[dannyo013]

I was wondering if there is a way to make this with a 1/4" input jack for electric guitars. Would make a great portable amp.

[-Syrus-]

How 'bout just adding a 1/4 jack and trying it out?

Dunno about the input impedance...But try it :P

If you are smart you might wanna build something like:
http://runoffgroove.com/littlegem.html

Easy as pie

or

http://www.beavisaudio.com/projects/NoisyCricket/

Better version ! :P Props to Dano the designer.

These are all based upon the allmighty Smokey amp.
Maybe you should just buy one of those ;)

[Daxuto]

Thanks for that, the little gem is pretty much exactly what I needed.

[robot1398]

but they need ic this dosent
so i prefer this one

[-Syrus-]

Then please, tell me what is wrong with using a IC?

OP-Amps circuit mostly use IC's for the bigger gain they can deliver.

LM386 is the most used audio amplifier in DIY and guitar effects.
Its reliable, sounds good and is easy to work with.( As in one chip and two capacitators is the bare minimum for a working guitar amp. eg Smokey amp by Zinky electronics)

So please don't give your opinion.

[Mr_mojo]

Sometimes it's easier to obtain some components such as transistors and capacitors, whereas specific ICs have to be purchased. I for one will be building this as opposed to one of the better ones which use an IC for that very reason, I'm on a very low budget and have these components (or similar once which will suffice) to hand. Just so you know you've brought an extra member to Instructables. I was looking for a schematic for a simple push pull audio amplifier when I found this one, and on reading your comment and finding it so rude I thought I'd sign up and give my reasons for wanting a simple amp as opposed to one that would require me to purchase anything.

[plmqaz1243]

Wonderful world we live in, when people are shunned from giving their opinion by some guy who... I don't even know what you do. Great job.

The misspelled word of the day is:
Mispell

[building_boy]

Not asking, commenting he is sooooo cute!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!

[T-K]

Do I.C. Mr Resistor?

[spystealth1]

That's an interesting way of creating a project box. Usually someone would get some sort of plastic container and paint it, but you use a kind of cardboard wood and instead of paint, you use paper.

[robot1398]

some pics

[Biggimac]

Had to ask!
On your strip board, why did you put your components so far from each other?
They won't bite each other!!

[robot1398]

i know but i had of this size and that time i was not knowing how to cut a strip board

[Mr_mojo]

You use a sharp stanley knife (thats what we call them in the UK but I've seen them called box cutters on here?!) anyway you just score it with the knife then snap it.

[didgitalpunk]

what is the capacitor voltage? i don't think a 35V 10 uF one would do right

[brunoip]

yes, it would work, it is just have a bigger size but it will do fine.

[didgitalpunk]

but will it act exactly the same?

[brunoip]

yes it will

[Tyto Productions]

What kind of speaker did you use? It looks like a computer speaker. Would any speaker work?

[brunoip]

any 8 ohm speaker will work

[schumi23]

Great ible!
"Ps: I'm from Argentina so let me know for any grammar mistake"
Well, i only found one:
It would be more proper to say "Let me know about any grammar"
Ive been looking for an ible like this all over instructables, and have finally found it thanks to you:) Thanks!

[usbg3rd]

it is not properly biased it clips the portion of the audio signal (negative crust)

[usbg3rd]

hello
can u please tell me what is the output power of the amp ???