So lets get started!
Please don't be too critical, I'm only 14!
Step 1: Parts
OPA2134PA op-amp. There are alternatives but I have had most success with this one. The only other one that I would recommend is OPA2132
1x IC socket
2X 470uf or higher 10V capacitors
2x stereo audio jacks
2x 0.2uf MKT or pollyester capacitors
2X Pannel mount LEDs
1X NPN transistor
1 or 2 9V battery clips
male header pins
1X stereo 10k potentiometer
10k, 100k, 1k, 4.7k, 47ohm resistors (I got packs of 8)
2x SPDT micro switches
3v button cell and holder
A PROJECT ENCLOSURE! Be creative!
Step 2: The POWER Section
1. mark a line with a width of 2 holes right down the PCB board. This will be the ground.
2. Solder in the male header pins for + and -
3. Now solder in the Two 4.7k resistors.
4. Solder in the 470uf capacitors
5. Look at the diagram (pic 5) and look closely at the "stray" resistor. this is 1k and it's for the power LED
6. try and solder it so it's as compact as possible
In the diagram, the green lines represent the under-board connections. They are usually made with jumpers or solder. In the last picture, I have an example of the under-board connections or "green lines"
Don't worry about the other parts in the last picture, they are for later.
Step 3: The IC Section
First we solder in the IC socket for the OPA2134PA. DON't INSERT THE IC YET!
Next we solder two 100k resistors from the ground strip the pins 5 and 3 of the IC socket.
Then we solder in the 1k resistors from the ground strip to pins 2 and 6 of the IC socket
Picture 2 is a pinnout diagram for the pins.
Now solder in the 0.2uf capacitors. Solder one pin of the capacitors to the 100K resistors (pins 5 and 2)
Solder the 10k resistors, like the capacitors to the 100k resistors, to the end of the 1k resistors.
Now solder the 47Ohm resistors to pins 1 and 7.
Now connect the ends of the 47ohm and the 10k resistors
Now at header pins to the connected ends of the 10k and 47ohm resistors and the other end of the capacitor.
Now it should look like picture 8
The last step for this section would have to be to connect the power supply to the op-amp. The + connection will go to pin 8 and the - voltage connection will go to pin 4
All done on the circuit!
Step 4: The LED Flasher Circuit
Step 5: Wiring Everything Up
Jack L+R ⇒⇒ Potentiometer L+R ⇒⇒Audio in L+R ⇒⇒ Audio out L+R ⇒⇒ Jack L+R
Make sure all solder connections are good
Step 6: Close Up the Case
Step 7: Finished!
If you find this instructable insufficient to build a headphone amp, LET ME KNOW so I can improve it.
If you have and problems, head over to here to troubleshoot.