Lots of progress has been made during the last 6 months.
Design finalized, circuit prototyped, PCBs designed and manufactured,
components fitted, circuit tested and debugged (partly still in progress) ..
Some of the pre amp and fundamental extraction circuitry is built by hand on perfboard or breadboards. The remaining boards, 3 double-sided and 1 single-sided, are all done.
Making your own boards like this is hardly worth it considering how relatively easy it is to have a board house make the PCBs for you. However, buying this many boards from a fab house would be pretty expensive, especially when I probably won't bother with more than one unit. So in this case, a single run, prototype through hole.
Some photos of the etching process;
|Sample of the PCB designs.|
|Etching in a etching tank.|
|Preview of the result.|
|All PCBs etched.|