Cool. I was looking for a place to solder though so I soldered to the inductor connected to that jumper.

It works fine. Sound quality is good considering I'm not using anything other than the DAC to drive the auxiliary of my home stereo. I need to hook it up to a decent system to test it for sure. I will probably connect it to my PC sound card and do a spectral analysis of some pink noise to see the subwoofer roll off.

My kernel stuff all seems to work OK too - only prob is a slight thump when changing the crossover frequency to a lower value (i.e. 100 to 80 Hz but 80 to 100Hz is fine)

There is however some noise getting in somewhere when I turn the gain of my amp right up (at normal levels you can't hear it), but I would guess that it is getting in on my breadboard (or the power supply lines) more than anything. Sounds kinda 50Hz-ish so I think that will go. I will do some PCBs next week some time.

In all an easy job - I only spent about 5 or 6 hours from whoa to go. I can put up some quick pics of the hack on Monday...