diff --git a/Components/OPL2/OPL2.hpp b/Components/OPL2/OPL2.hpp
index ed631b262..647cc3ff5 100644
--- a/Components/OPL2/OPL2.hpp
+++ b/Components/OPL2/OPL2.hpp
@@ -334,9 +334,10 @@ struct OPLL: public OPLBase<OPLL> {
 			int level = 0;
 		};
 		void update_all_chanels() {
-			for(int c = 0; c < 6; ++ c) {	// Don't do anything with channels that might be percussion for now.
-				channels_[c].level = (channels_[c].update() * total_volume_) >> 14;
-			}
+//			for(int c = 0; c < 6; ++ c) {	// Don't do anything with channels that might be percussion for now.
+//				channels_[c].level = (channels_[c].update() * total_volume_) >> 14;
+//			}
+			channels_[0].level = (channels_[0].update() * total_volume_) >> 14;
 		}
 		Channel channels_[9];
 
diff --git a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachine6502.mm b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachine6502.mm
index bc58b91c1..635005613 100644
--- a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachine6502.mm	
+++ b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachine6502.mm	
@@ -23,7 +23,7 @@ static CPU::MOS6502::Register registerForRegister(CSTestMachine6502Register reg)
 		case CSTestMachine6502RegisterA:					return CPU::MOS6502::Register::A;
 		case CSTestMachine6502RegisterX:					return CPU::MOS6502::Register::X;
 		case CSTestMachine6502RegisterY:					return CPU::MOS6502::Register::Y;
-		case CSTestMachine6502RegisterStackPointer:			return CPU::MOS6502::Register::S;
+		case CSTestMachine6502RegisterStackPointer:			return CPU::MOS6502::Register::StackPointer;
 	}
 }
 
diff --git a/OSBindings/Mac/Clock SignalTests/OPLTests.mm b/OSBindings/Mac/Clock SignalTests/OPLTests.mm
new file mode 100644
index 000000000..aad765787
--- /dev/null
+++ b/OSBindings/Mac/Clock SignalTests/OPLTests.mm	
@@ -0,0 +1,26 @@
+//
+//  OPLTests.m
+//  Clock SignalTests
+//
+//  Created by Thomas Harte on 14/04/2020.
+//  Copyright © 2020 Thomas Harte. All rights reserved.
+//
+
+#import <XCTest/XCTest.h>
+
+#include "OPL2.hpp"
+
+@interface OPLTests: XCTestCase
+@end
+
+@implementation OPLTests {
+}
+
+- (void)testADSR {
+	Yamaha::OPL::Operator test_operator;
+	Yamaha::OPL::OperatorState test_state;
+
+	
+}
+
+@end