here’s an initial PCB test for the Triode tube overdrive on the SMBA site. this picture is pre-sanding. it was milled using LinuxCNC on a Xubuntu 14.04 LTS running the Xenomai-188.8.131.52 kernel version 3.5.7. it’s taken some time to get the configuration working and compiled since i didn’t want to use the live CD. the CNC machine is a Chinese 3020T that i got off eBay. the board layout was done in EagleCAD using the PCB-GCODE ULP script.