I really like this project, and because imitation is the sincerest form of flattery, I copied it
I added two upward facing pink LEDs (Mouser P/N 604-WP7113VRVC1C) to illuminate the black pin fins, and also a "breathing" blue LED
(sold HERE) for the On/Off pilot light.
I added a "PO89ZB" power supply filter circuit
(LINK) on the round PCB, to remove switching power supply noise. The filter components are in the top right corner of the board, at 2 o'clock.
Finally, I got rid of the expensive 2SK170 / LSK170, and replaced it with a Fairchild J112 which costs less than $0.65.
A huge thank-you to Nelson Brock for inventing and unveiling this project! I hope he decides to make it available to diyAudio members in some way, possibly bare boards, or partial kits, or full kits, or downloadable Gerber files. He deserves to be economically rewarded for his hard work.
However, if he decides not to, and if he gives his permission, I'll make this "RACAM" available to members. Probably in a new thread.
Mark Johnson
(8 attachments below, schematic is the last one)