Headphone Amp (Chu Moy)

Step 9 Completing the build

As you will see from the image below, all the connections for the jacks and pot are listed, take a few minutes to understand it all.

the images really do all the talking in this part

Once this is all hooked up correctly, solder your power source (9v battery) and turn it on.
before you plug anything in have a feel around all the components checking for any heat, if it does get hot, take out the battery and check the underside for solder bridges and shorts, also make sure everything matches the diagrams.

Next plug in only your headphones and put the gain up full and listen for any static, if all is good then plug in your mp3 player and take it for a test drive. once again if anything isn't working check the circuit as above

now you may have noticed you cant get much further than half way without suffering from distortion, this is due to the high gain, we will now replace R3 with resistors that will lower the gain now we know the circuit is stable.

2.0 K© gain 6
2.5 K© gain 5
3.3 K© gain 4
4.7 K© gain 3
10 K© gain 2

I replaced mine with a 2.2k©stor for a gain of around 6 and this worked well for me.

once you are happy with the gain, you can get to putting it in the tin

Note: The images of the finished amp used in this instructable show another cmoy i have where a Panasonic pot was used and a toggle switch was used in series with the power supply.

Comments

[jdubaya]

where is the DIP-8 IC sockets, gold contacts? what are they, what do they do, and are they required?

[Cew27]

The socket for the op-amp is soldered onto the board as soldering the amp directly would damage it.