I builded it and works well. Good. However, compare to the other vibe pedal (include Vibronaut pedal) Photonvibe's maximum speed is slower than any other vibe pedal. At maximum speed, mine is 75% speed, IMHO. (
Yes,, I have to change some component's value. R14, R15 both resistors are limit of speed, so I'll change to 2k2. Most of all, I have to change R8 resistor to 4k7 for more natural vibration.
This Mod is "Closer to Univibe". R8 -> 4k7 3k3 and 4k7 is ratio of original Uni-vibe.. If you feel your Photonvibe's vibration is not good, change R8 to 4k7. It makes more natural vibration.