I figured it would be easiest to connect the LEDs on a a daughterboard, something like this:
or for 5mm LEDs
or you could just wire the LEDs together in the box.
You could only use 5 LEDS if you wanted to, and take output 1,3,5,7,9 from the IC for best resolution. Or configure the LEDs basically and way you want to, from inside - out, different colours ect.
At first I made a layout from a much simpler schematic without the op-amp, but that didn't work out well with guitar signal.
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