Picture of How to make a pocket headphone amp!
In this instructable, I will be showing you how to make a  headphone amp. If you have some big headphones such as Sennheiser, beats by dre or some other big headphones (in my case, some sony MDR-XD100) an or an MP3 player isn't enough, especially if they have a high impedance. This circuit was originally  developed by a man by the name of and it has been extremely popular. There is only one difference with mine (and most others) and that is the fact that he used two single op-amps and we will be using a dual op amp.
So lets get started!

Please don't be too critical, I'm only 14!

Step 1: Parts

Picture of Parts
Here are the parts you will need:
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


chillrov1 year ago

sir can i have a clear schematic please?

dog digger (author)  chillrov1 year ago

Schematics are available from tangentsoft and here's a link from their site: http://tangentsoft.net/audio/cmoy/misc/cmoy-tangent-sch.pdf

rotem2 years ago
how do i make the left channel and the right channel to one 3.5 mm connector

i mean how do i connect it to 3.5 mm jack and make it stereo
dog digger (author)  rotem1 year ago
On the stereo connector, you should have 3 pins. Left, Right and ground. If yours only has 2, then you have a mono connector
nkhoo2 years ago
Can you explain what the header pins are for? I apologise for my inexperience but i am very blur. Any explanation would be greatly welcome. Thank you in advance
dog digger (author)  nkhoo1 year ago
Sorry for the very late reply but I used them because they make it easier to solder wire to the PCB so if something goes wrong, it's easier to troubleshoot
can you draw up a diagram of the circuit and send it to me
mdog933 years ago
Will ANY NPN transistor work? What criteria does it need?
agm88 mdog932 years ago
oh and an s9014c transister is pre amp low noise and low level transister
but i would rather use a bc548 for the LED synce
agm88 mdog932 years ago
any NPN general purpose transister will work like for example
2n4401 works quite well
and bc548 which is eqivalent to a 2n3904
Knerps2 years ago
This looks great, +1 EET1982, can you provide a single schematic?
EET19823 years ago
Very cool instructable. I will be building it soon. Would you happen to have a full schematic of the circuit?
jeddlestone3 years ago
will 2 470uF 16V Radial Electrolytic Capacitors work instead of 10V rated?
antmanadam3 years ago
Can you tell me what exactly what pot you have an where you got it
dog digger (author)  antmanadam3 years ago
It's a 10kohm dual log potentiometer (generic) found at my local electronics store.
Would a BC548 work for this application?
The only other ones I have are S9014C.

Are either of these ok for this purpose?
dog digger (author)  mdog933 years ago
Any general purpose transistor will work so yes, they will work
toj cookies3 years ago
nice job
lewster3 years ago
nice instructable, dog digger!
jman 313 years ago
Nice job! It's great to see young people like yourself getting interested in electronics!