DIY headphone amplifier – JDS labs CMoy bass boost version 2.02

With the stress of Alissa’s terrible twos and the impending birth of the two terribles, I’ve been taking on little projects here and there. The bike was one of the more ambitious projects. My latest project, though less ambitious, is new territory for me.

It’s new territory because it’s an electronic device which is not intuitive to me at all compared to the mechanical things I’m used to tackling. Anyway, without further ado, here it is:


What is it? It’s a headphone amplifier. Stuffed into an Altoids tin. Much like big speakers need amplification to sound their best, headphones also can sound better with stand alone amplification. It’s based on a simple inexpensive home brew design originally dreamed up by Chu Moy (which is why these are called CMoy amps.). Since the original incarnation, many folks have tweaked it to suit their needs. Some have built and sold them on ebay. Others have started small businesses providing parts and advice.

One of those businesses is JDS Labs. They provide the assembly guide, bill of materials, and the printed circuit board to guide you through the process. John, the man behind JDS was super responsive and really helpful in answering my questions and getting me parts quickly.

After reading the instructions multiple times and picking up some ancillary supplies, it took me about three hours to put the whole thing together. And to my surprise, it worked without having to do any trouble shooting! I probably could have taken my time a bit more on getting the holes in the tin more exact, but it’s not bad.

As for performance, it definitely improves the sound quality of my ipod and even the signal coming out of my Mac Pro. Everything is more detailed and “live” sounding. I will say that different combinations of songs, headphones, and sources provide different levels of improvement. The bass boost is thankfully not boomy or obnoxious at all. As a matter of fact, with the cheapo headphones I’m using now, I’d probably just leave the bass boost on all the time. I might feel differently after my new cans arrive next week though.

Since this is my first headphone amp, I don’t really have anything to compare it to. But as far as DIY projects go, this one was fun, rewarding, and not that expensive. And actually, since the parts were relatively cheap and I figured I would break something along the way, I ended up buying enough parts to make three. So I guess I have to start eating some Altoids!

EDIT: 1/25/09
I ended up finishing the other two amps. One is simpler in that I eliminated the bass boost knob. Here’s a pic before putting it in the peppermint altoids tin.
The other retains the bass boost knob but moves it to the stock location. This one went into a wintergreen altoids tin.

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