We can decide what circuit is active on any given channel by engaging the circuit.

Engaging the Mic Preamplifier Circuit

!SSL Duality - Central Routing Panel and TFT Screen - Engaging Mic Preamplifier Circuit.excalidraw.svg

Working backwards, what feeds the Channel Input Patch point?

Engaging the Line Preamplifier Circuit

!SSL Duality - Central Routing Panel and TFT Screen - Engaging the Line Amplifier Circuit.excalidraw.svg

Working backwards, what feeds the Monitor Input Patch Point?

Engaging Both Circuits at the Same Time

!Engaging Different Circuits .excalidraw.svg