If you’re serious about your headphone amps, you probably already know about the M3 headphone amplifier. Instead of going for the extra tiny, they’re going the ‘screw the size, it’s all about the sound’ route. Thsi thing needs a 24v .5amp power supply. Boards are available, and the discussion has gotten so long on headwize that they exceeded the maximum thread length.
I got busy with the laser last night and came up with something new: a custom etched track pad. It still works, with a bit of added texture where I introduced it to the warm glow of the laser. Hit the link for pics and a walk through.