This portable pocket speaker and amplifier will work with any mp3 player or similar, e.g zune, ipod, laptop, etc etc....
This project is a small speaker / amp that you can shove in your pocket. I will describe how to build your own speaker and amplifier.
Its main parts are:
- -A small amp kit that you will need to construct
-A small speaker
-A 9v (or any other battery you can squeeze in)
-A stereo jack (like the end of your headphones)
-A tobacco tin to put it all in, you can use what ever container you want
That’s pretty much it
First things first you will need to buy something but its only £7.99 and that’s for the whole of the amp kit
I used this one, here:
http://www.velleman.be/ot/en/product/view/?id=9181 (7W mono amp)
Mine cost £7.99 from Maplin:
http://www.maplin.co.uk/Search.aspx?cri ... ce=15&SD=Y
You’ll need to make sure you have got the following:
- -Soldering iron
-Wire
-Solder
-Stereo jack
-Container / tin
-Speaker
-Drill
-Wire cutters
-Pliers
-Flat head screw driver
Once you have bought your amplifier kit, follow the instructions that came with it.
BUT WAIT!!...
If you're going to mount it in a 'standard' sized baccy tin (like i did) then you will have to solder the two large capacitors on about 3-4 inches of wire (TAKE CARE/NOTE OF POLARITY!!) so that they can be lade flat either side of the loudspeaker and not be crushed by the lid.
You will now have a working amp (hopefully
) I'm going to assume it works and just go on without testing it, however I would recommend testing it 
your speaker needs to be able to fit into the box/container that you have chosen to use. I happend to have a baccy tin and speaker that fitted together perfectly:
Okay so you have an amp that you have just soldered together, a speaker and battery and some wire... pretty much anyway.
get one of those 9v clip wires:
Solder the ends to the amp to the two pins that stick out together at the middle of the front. (sorry, here's a pic):
I don't think I need remind you of getting the polarity correct but I have anyway
i have just remembered... an a switch in series with your battery so that you can leave it plugged in and just use a switch rather than have to wrench out the 9v every time you don't use it.Right that's the power sorted for the amp, now the speaker...
I used a 16 ohm 1.5W speaker which works great for me and for the amp... you can try other ratings and qualities etc but this is just the speaker i had at home that i knew would work. from my limited knowledge of electronics I think it is pretty important to have a resistance of about 16 ohm when using a low power amp such as these, however like I said experiment and leave a post saying how it all went...
Solder the speaker's terminals using some of your wire to the (looking at it from the view of the pictures) right hand two pins (with LS (loudspeaker) written on) that stick out together from the amp.
The two remaining pins that stick out of the amp (to the left) are for the input signals...
take your stereo jack...
...and attach three wires to the terminals, ground, 'left signal' and 'right signal'.
The ground is usually the larger terminal that is the one that holds the wires at the end with small bendable in gripping part
As you're using a mono design (i.e. one speaker) then the two signal wires need to be connected together so there is no loss of signal. To do this without putting extra load onto your player (which is bad...) use 2 resistors, connect both signals together via these resistors.
left-----------|resistor|----\
----------------------------------\___________combined signal________
----------------------------------/
right -------|resistor|-----/
So now you have two wires coming from your jack (one of the wires is the two combined signal wires) attach these wires to the amp on the remaining pins as I said before for the input signal.
no you need to mount things in your container/tin luckily for me I used a tobacco tin so my speaker magnetically stays in position
the only thing I mounted was the amp to do this remove the heat sink (only if you have a metal box) then drill a small hole in the tin where the chip on the amp will be against and use the whole tin as the heat sink. I did this because it just don't fit with the heat sink on AT ALL!
Another important note while you mount it all keep everything insulated form the tin and from each other.
Here's my layout and mounting pics:
Anything I have missed or not covered in enough depth just leave a post and I will be happy to explain and give you a hand
OR if I have done this in a bad way and you can improve on it post your improvements too!I would also love to see your version of this...?
NB: I recommend a rechargeable 9v 'cos they're an expensive way to buy energy!
Enjoy
