VCA_1: add note about ringing

VCA_1/VCA_1.kicad_sch

@@ -2112,6 +2112,17 @@
 		)
 		(uuid "0efa94b4-b652-49c8-99e5-78f30c32aa27")
 	)
+	(text "* NOTE: after testing on a real PCB, there is ringing with square,\n	and sawtooth waveforms after the differential amp. Maybe try a\n	faster op-amp, or add some capacitance to the feedback network.\n	18pF is too large for the 1M resistor though. probably need to\n	use smaller resistor values for R11-R14."
+		(exclude_from_sim no)
+		(at 209.804 75.692 0)
+		(effects
+			(font
+				(size 1.27 1.27)
+			)
+			(justify left)
+		)
+		(uuid "451ecbdf-247e-47ec-ba27-d4ae713a7aa9")
+	)
 	(text "* -5V at\n  ~200uA"
 		(exclude_from_sim no)
 		(at 119.38 100.584 0)
@@ -4160,7 +4171,6 @@
 		(in_bom yes)
 		(on_board yes)
 		(dnp no)
-		(fields_autoplaced yes)
 		(uuid "1d732f6a-b198-4109-b4d6-f77008bbc970")
 		(property "Reference" "#PWR010"
 			(at 199.39 78.74 0)
@@ -4992,7 +5002,7 @@
 				)
 			)
 		)
-		(property "Value" "680k"
+		(property "Value" "470k"
 			(at 104.14 93.98 90)
 			(effects
 				(font