Not a lot out there on this one. It's a optical noise gate DOD produced in the late 70s and works best at the beginning of your signal chain. The original had a very strange way of bypass switching, but I've omitted this as your true-bypass method of choice is probably much superior. Originals used a VTL5C2, but experiment with LED and LDR combos, and possibly the value of the resistor feeding the LED (10k right above the LDR and Q1).
![]()
