Saturday, December 20, 2014

DIY headphone distribution amplifier

Sometime back in 2007 I was in need of a headphone distribution amp. I couldn't find a device for any reasonable price, so I had to make one myself.

The completed headphone amp in 2007

Then I happened to find the PAiA 9206K Headphone Distribution Amp. At the time I couldn't afford to buy it, but I was in luck as PAiA provides schematics for their devices. I love it when companies do that!

So I sourced the parts and built it myself. Now I owe PAiA one! I'll keep them in mind when it's time to start building my modular...

Insides with the op amps and pots soldered. Input and output jacks are still missing.

The schematic is very simple, and you can easily see how to add/remove channels if needed. The PAiA kit has 6 headphone outputs, but I needed only 4.

Use low-noise op amps that work with a supply of +6/-6 volts. Unfortunately I don't remember what op amps I used... They might have been TL072. Using a dual op amp makes for 1 op amp per stereo headphone channel.

The insides completed. Not very pretty wiring, but it works just fine!

Fitting it in, almost ready.

Now only missing some paint...

For the project case I used an old speaker. When painting it I tried to do some stencil work but that failed miserably as you can see...

The device works and is in use to this day. Thanks to PAiA!