Build Your Own Headphone Amplifier
Do you ever ride using headphones to listen to an MP3 player? I do and my MP3 player just did not have enough volume for me to hear above wind and road noise. I started investigating options for amplifying my MP3 player and this is what I found. You can build one completely from scratch, but I am not that electronically inclined yet so I looked for another solution. That one was affordable but not very good. Then I found an easier way. Here is how I built a pretty easy Headphone Amplifier. All it takes is a kit from an electronics parts store or internet, 2 - 3.5mm stereo audio jacks, a 9volt battery connector, some wire and an Altoids tin.
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Here is what you need. I happened to find this 1 watt amplifier kit in an electronics store in town. It was $7.65 and works pretty well. I had to also buy a box for it and the Altoids tin fit the bill, $1.50. I had to buy 2 stereo jacks, $0.95 ea, and a 9 volt battery pigtail, $0.95, and a mini toggle for the power. I already had wire, wire cutters, drill, drill bits, soldering iron and solder.
The kit comes with everything you need for the basic amp. All resistors and capacitors and even the potentiometer (volume control). The PCB (printed circuit board) has the layout printed on it in white ink. All you have to do is follow along and solder the right pieces in the right places. I put the IC mount first then I soldered all of the resistors in place then the capacitors. I soldered wires to the board so that I could mount the Pot (potentiometer) in a different place. Then it is just a matter of wiring your jacks, power switch and battery.
Once all of the pieces are connected you should test it out. Turn the volume control all the way down, connect the headphones and audio source (cd player, radio, mp3 player, etc.), then connect the battery. Turn everything on and slowly turn up the volume control on the amp. If you have any problem I would say it is either in your input or output connections. After all is checked then you can use a drill and appropriate size drill bit to create openings in the Altoids tin for the volume control, power switch and audio jacks. You can see my configuration here. This configuration allowed the shortest run of wires. I also used some heat shrink tubing to protect the switch and the audio jacks.
I did buy one of the more complicated amps from a guy on eBay. It works well and the PCB is considerably smaller... almost too small. I don't know... I like mine better but that is probably just because I built it myself.
I hope this has been helpful for you.
