minimal build guide - mxmxmx/spinFV1 GitHub Wiki

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note the middle pin (labelled wet) near R7 / the vactrol: it's unused (connected to the one LDR leg of the vactrol), but this is where you could alternatively tap the (buffered) wet signal.
the output amp is the standard non-inverting configuration, amplify to taste. i went for ~ 4x (grrr = 10k, fb = 33k), which works pretty ok.
the caps near the power entry should be 22uF (25v+) or more.

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note the electrolytics are best put on the bottom side (other than what the silkscreen suggests); unless, that is, you use tall enough pin headers/sockets/standoffs and/or use small enough caps.

non-main

absolutely make sure you solder the 2-pin socket (gnd and power for the attiny) BEFORE soldering the 2x4 socket.
don't populate the pad labelled 1k*, it doesn't serve a purpose (or to be precise, it could/can be used as the series output resistor if the vactrol mixer was omitted and the wet signal routed straight to the output jack).

the attiny + tact switch is assuming the role of the typical 8x switch you'd see with FV-1 boards; the firmware is simply cycling through the 8 programs. not very user-friendly but does its job.
programming the attiny: is done with an ISP programmer or an arduino (which is what i did). for this to work, you'll need to use the internal oscillator, 1MHz will do.
moving the spin code onto the eeprom: can be done with an arduino, too. the example program does just that. in this case, the actual code is stored in the flash: const PROGMEM uint8_t image[] (in diskimage.ino). to extract the binary from the spin HEX file, you'd do:

arm-none-eabi-objcopy -I ihex -O binary spin.hex spin.bin

xxd -i spin.bin