so I can hear music over my MP3-player whilst building stuff.
I got my hands on some old computers and tried to use only them as part source,
and here it is: The zero-cost amplifier!
It is build of a CD-drive with headphone output.
The first thing I had to do was searching the amplifier circuit on the front panel board.
|The front panel board without the end position switch|
It's on the left half.
The next thing was finding the chips datasheet.
|The amplifier circuit with the MS6038|
It looks like an opamp and it's also that easy to use.
Now I cut it from the rest of the front panel board and desoldered the 3.5 mm terminal.
After this I pulled wires from the circuit to this terminal and to two external speakers I got from old PCs.
I used a mobile phone charger with 230V input and 5V output as voltage source,
but you can also use any other kind of power supply from 2.7 to 5.5 volts.
Finally, I built a small free air circuit to make use of the busy LED.
It contains of a capacitor with 3.3µF and some resistors to make it glim when the amp is in "standby" and light when music plays.
I got all this parts out of my toolbox, so they were "free" to.
I found out that this kind of circuit is very likely to be in all kind of cd players.
Here is a photo of an portable CD-player.
|Alternative circuit out of a portable CD-player |
If you once need such an amplifier, you know how you get one for zero cost!If I have updates, I'll post them in this blog, so keep looking.