This one was ordered by my friend who needed three loops instead of two. Also, the buffer switch in Circumference 1 was too close of the channel 2 switch to be used on stage. The layout is pretty much the same:
Third loop is added, and the fourth LED is indicating if the power is on or not. With buffer off this works without a external power source, but the channel LED’s of course won’t work. Without a buffer circuit this could be whole passive, and there could be a battery inside the enclosure just to power up the indicator LED’s.
Let me mention that compared to simplicity of the circuit, these are quite toilsome.
Blackout Circumference 2: