Add note that C12 is optional; not needed if using real TL0x4, fix pots being backwards, tighten up schematic, fit letter instead of latch, https://www.neutrik.com/en/product/nc3fav1-0 A Series, 3 pole male XLR receptacle, grounding: mating connector shell and front panel, horizontal PCB mount, black chrome shell, https://www.neutrik.com/en/product/nc5fbv-b B Series, 3 pole female XLR receptacle, grounding: mating connector shell and front panel, steel retention lug, vertical PCB mount, https://www.neutrik.com/en/product/nc3mbv-sw B Series, 3 pole male XLR receptacle, grounding: separate ground contact to mating connector shell and front panel, horizontal PCB mount, http://cherryamericas.com/wp-content/uploads/2014/12/mx_cat.pdf Cherry MX keyswitch, 2.25u, PCB mount, asymmetric push, https://www.neutrik.com/en/product/nc3faah1-da AA Series, 3 pole male XLR receptacle, grounding: separate.