I made this little amplifier out of parts I pulled off of dead electronics so a more appropriate name would be a JunkAmp.
Here's a schematic I put together for people to reference. Download it by Right-Clicking then "Save as..." or "Save Link as...".
The image gets cutoff but just Right-click and "View Image" to see it all.
Here are the parts you will need.
LM386 Amplifier chip (8 pins)
10 ohm Resistor
10 microFarad (uF) Polarized Capacitor
220 microFarad (uF) Polarized Capacitor
0.047 microFarad (uF) Non-Polarized Capacitor
One Speaker: 8 ohm, 0.5 Watt speaker (I used a 8 ohm, 2 watt speaker in the video).
One 1/4 inch audio plug jack.
One 9 volt Battery.
One 9 volt Battery connector.
PCB Board
Wire. It's easier to use stranded wire, since it is more flexible.
Notes:
Polarized means there is a Positive and Negative end of the component. For the Capacitors, there is a white stripe on the side of the cylinder that leads from one of the leads (pin). That stripe indicates which side is Negative.
Since we are using a 9 volt battery for this project the Working Voltage of the Polarized Capacitors have to be higher than 9 volts, or else you will damage the Capacitor. The Working Voltage is usually written next to the White Stripe that I mentioned above and is just written as "9v" or greater.
The non-Polarized Capacitor does not have a polarity (+ -)so it doesn't matter which way it is positioned. Since the non-polarized capacitor is so small, the numbers on it will be written as "473" to indicate it's a 0.047 uF capacitor.
Edit: Jan. 17 2011
I've gotten a few questions about adding additional features and so I drew up a second schematic that shows how to add an LED for an indicator light, Power switch and a volume pot.
To add a little distortion, remove the 10 uF capacitor and replace it with a simple wire connecting Pin 1 and 8. The capacitor stabilizes the sound wave, but removing it will cause some distortion. Keep pin 1 and 8 connected though, this keeps the gain as high as possible.
If you have any questions, just email me at aDimWit@hotmail.com
Mini Guitar Amplifier by Justin Bread is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
Both images embedded on this post are Attribution-NonCommercial Creative Commons licensed.
14 comments:
can you tell us and show at the same time how you make it?? plz
"non polarized are marked as blue, right?
Non-polarized capacitors are small and disk shaped. The polarized capacitors are cylinders. Polarized capacitors also have a voltage rating (10v or 35v or something). Non-polarized capacitors will just have a three digit code stamped on it to determine its value. All of these capacitors will have varying colors.
If I replace the 10uf capacitor with a potentiometer, will that work as a volume control?
If not, how would I do that?
To add a volume control, get a 5k Ohm potentiometer and attach the center pin to pin 3 on the LM386 IC. Then attach the Input positive pin, to one of the side pins on the pot. The other side pin should attach to the ground.
If that doesn't work e-mail me. (adimwit@hotmail.com)
i have followed the instrucctions and it doesnt wokrs! the only difference is that im using a JRC 2073D chip, but I think that it has the same characteristics than LM386... can somebody help me? my email is kelmi_12@hotmail.com thanks
I also want to add an LED. Where do I position it?
To add a resistor, connect a 1k to 4k ohm resistor to the LED. Then you can just attach it to the 9 volt and ground.
1)
can this amplifier be used in ipod also,,,,if no then what can i do,,
2)in making of this amp can i use jrc ic instead of lm386 ic...
1. Yeah, you can use it to amplify an iPod but this schematic is only mono. The iPod is stereo. You are going to need two LM386 wired the same way to work with a stereo jack.
You might need to use a different schematic as well for higher quality audio. Search Instructables.com, that's a great resource.
2. Yeah, the JRC386 should work. I think it's a copy of a later version of the LM386 but it should work with this schematic.
Hey I built this amp just a couple of days ago. Not to bad! Workes pretty good. Only made a couple of changes with the gain, but sounds great. Thanks for the schematic.
Hi,
I was wondering if you would be able to control distortion by adding more capacitors in series to pin 1 & 8 with a switch to them, thus allowing the value to be varied between 10uF to 0 for more tone settings? Would it work since the 0uF equals distortion, and 10uF = no distortion - or am I getting it wrong?
@Axel1334
Yeah, If you remove the capacitor and replace it with a simple connection, it will distort, and you can get varying distortions by add different capacitors in there.
Thanks!
I hope you don't mind but I took the liberty of sending you an e-mail to ask you if this would work with a fixed-gain amp I have at disposal.
And thanks for the post, it's great to be able to these kind of project at home.
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