diff --git a/Analyser/Static/AppleII/Target.hpp b/Analyser/Static/AppleII/Target.hpp
index 0ad262201..f08bf1f68 100644
--- a/Analyser/Static/AppleII/Target.hpp
+++ b/Analyser/Static/AppleII/Target.hpp
@@ -34,12 +34,14 @@ struct Target: public Analyser::Static::Target, public Reflection::StructImpl<Ta
 	Model model = Model::IIe;
 	DiskController disk_controller = DiskController::None;
 	SCSIController scsi_controller = SCSIController::None;
+	bool has_mockingboard = true;
 
 	Target() : Analyser::Static::Target(Machine::AppleII) {
 		if(needs_declare()) {
 			DeclareField(model);
 			DeclareField(disk_controller);
 			DeclareField(scsi_controller);
+			DeclareField(has_mockingboard);
 
 			AnnounceEnum(Model);
 			AnnounceEnum(DiskController);
@@ -48,4 +50,8 @@ struct Target: public Analyser::Static::Target, public Reflection::StructImpl<Ta
 	}
 };
 
+constexpr bool is_iie(Target::Model model) {
+	return model == Target::Model::IIe || model == Target::Model::EnhancedIIe;
+}
+
 }
diff --git a/Components/6522/6522.hpp b/Components/6522/6522.hpp
index df8502f71..733fccd75 100644
--- a/Components/6522/6522.hpp
+++ b/Components/6522/6522.hpp
@@ -68,7 +68,7 @@ class IRQDelegatePortHandler: public PortHandler {
 		/// Sets the delegate that will receive notification of changes in the interrupt line.
 		void set_interrupt_delegate(Delegate *delegate);
 
-		/// Overrides PortHandler::set_interrupt_status, notifying the delegate if one is set.
+		/// Overrides @c PortHandler::set_interrupt_status, notifying the delegate if one is set.
 		void set_interrupt_status(bool new_status);
 
 	private:
diff --git a/Components/AY38910/AY38910.cpp b/Components/AY38910/AY38910.cpp
index c32df440e..625ffb6d0 100644
--- a/Components/AY38910/AY38910.cpp
+++ b/Components/AY38910/AY38910.cpp
@@ -376,6 +376,30 @@ void AY38910SampleSource<is_stereo>::set_control_lines(ControlLines control_line
 	update_bus();
 }
 
+template <bool is_stereo>
+void AY38910SampleSource<is_stereo>::set_reset(bool active) {
+	if(active == reset_) return;
+	reset_ = active;
+
+	// Reset upon the leading edge; TODO: is this right?
+	if(reset_) {
+		reset();
+	}
+}
+
+template <bool is_stereo>
+void AY38910SampleSource<is_stereo>::reset() {
+	// TODO: the below is a guess. Look up real answers.
+
+	selected_register_ = 0;
+	std::fill(registers_, registers_ + 16, 0);
+
+	task_queue_.enqueue([&] {
+		std::fill(output_registers_, output_registers_ + 16, 0);
+		evaluate_output_volume();
+	});
+}
+
 template <bool is_stereo>
 void AY38910SampleSource<is_stereo>::update_bus() {
 	// Assume no output, unless this turns out to be a read.
diff --git a/Components/AY38910/AY38910.hpp b/Components/AY38910/AY38910.hpp
index 0c21c1063..afb412e01 100644
--- a/Components/AY38910/AY38910.hpp
+++ b/Components/AY38910/AY38910.hpp
@@ -70,6 +70,7 @@ template <bool stereo> class AY38910SampleSource {
 	public:
 		/// Creates a new AY38910.
 		AY38910SampleSource(Personality, Concurrency::AsyncTaskQueue<false> &);
+		AY38910SampleSource(const AY38910SampleSource &) = delete;
 
 		/// Sets the value the AY would read from its data lines if it were not outputting.
 		void set_data_input(uint8_t r);
@@ -80,6 +81,12 @@ template <bool stereo> class AY38910SampleSource {
 		/// Sets the current control line state, as a bit field.
 		void set_control_lines(ControlLines control_lines);
 
+		/// Strobes the reset line.
+		void reset();
+
+		/// Sets the current value of the reset line.
+		void set_reset(bool reset);
+
 		/*!
 			Gets the value that would appear on the requested interface port if it were in output mode.
 			@parameter port_b @c true to get the value for Port B, @c false to get the value for Port A.
@@ -114,13 +121,15 @@ template <bool stereo> class AY38910SampleSource {
 	private:
 		Concurrency::AsyncTaskQueue<false> &task_queue_;
 
-		int selected_register_ = 0;
-		uint8_t registers_[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
-		uint8_t output_registers_[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+		bool reset_ = false;
 
-		int tone_periods_[3] = {0, 0, 0};
-		int tone_counters_[3] = {0, 0, 0};
-		int tone_outputs_[3] = {0, 0, 0};
+		int selected_register_ = 0;
+		uint8_t registers_[16]{};
+		uint8_t output_registers_[16]{};
+
+		int tone_periods_[3]{};
+		int tone_counters_[3]{};
+		int tone_outputs_[3]{};
 
 		int noise_period_ = 0;
 		int noise_counter_ = 0;
diff --git a/Machines/Apple/AppleII/AppleII.cpp b/Machines/Apple/AppleII/AppleII.cpp
index dace81906..ff9e19f67 100644
--- a/Machines/Apple/AppleII/AppleII.cpp
+++ b/Machines/Apple/AppleII/AppleII.cpp
@@ -15,7 +15,9 @@
 
 #include "../../../Processors/6502/6502.hpp"
 #include "../../../Components/AudioToggle/AudioToggle.hpp"
+#include "../../../Components/AY38910/AY38910.hpp"
 
+#include "../../../Outputs/Speaker/Implementation/CompoundSource.hpp"
 #include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
 #include "../../../Outputs/Log.hpp"
 
@@ -24,6 +26,7 @@
 #include "DiskIICard.hpp"
 #include "Joystick.hpp"
 #include "LanguageCardSwitches.hpp"
+#include "Mockingboard.hpp"
 #include "SCSICard.hpp"
 #include "Video.hpp"
 
@@ -41,17 +44,71 @@
 
 namespace {
 
-constexpr int DiskIISlot = 6;	// Apple recommended slot 6 for the (first) Disk II.
-constexpr int SCSISlot = 7;		// Install the SCSI card in slot 7, to one-up any connected Disk II.
+constexpr int DiskIISlot = 6;		// Apple recommended slot 6 for the (first) Disk II.
+constexpr int SCSISlot = 7;			// Install the SCSI card in slot 7, to one-up any connected Disk II.
+constexpr int MockingboardSlot = 4;	// Conventional Mockingboard slot.
+
+
+// The system's master clock rate.
+//
+// Quick note on this:
+//
+//	* 64 out of 65 CPU cycles last for 14 cycles of the master clock;
+//	* every 65th cycle lasts for 16 cycles of the master clock;
+//	* that keeps CPU cycles in-phase with the colour subcarrier: each line of output is 64*14 + 16 = 912 master cycles long;
+//	* ... and since hsync is placed to make each line 228 colour clocks long that means 4 master clocks per colour clock;
+//	* ... which is why all Apple II video modes are expressible as four binary outputs per colour clock;
+//	* ... and hence seven pixels per memory access window clock in high-res mode, 14 in double high-res, etc.
+constexpr float master_clock = 14318180.0;
+
+/// Provides an AY that runs at the CPU rate divided by 4 given an input of the master clock divided by 2,
+/// allowing for stretched CPU clock cycles.
+struct StretchedAYPair:
+	Apple::II::AYPair,
+	public Outputs::Speaker::BufferSource<StretchedAYPair, true> {
+
+		using AYPair::AYPair;
+
+		template <Outputs::Speaker::Action action>
+		void apply_samples(std::size_t number_of_samples, Outputs::Speaker::StereoSample *target) {
+
+			// (1) take 64 windows of 7 input cycles followed by one window of 8 input cycles;
+			// (2) after each four windows, advance the underlying AY.
+			//
+			// i.e. advance after:
+			//
+			//	* 28 cycles, {16 times, then 15 times, then 15 times, then 15 times};
+			//	* 29 cycles, once.
+			//
+			// so:
+			//	16, 1;	15, 1;	15, 1;	15, 1
+			//
+			// i.e. add an extra one on the 17th, 33rd, 49th and 65th ticks in a 65-tick loop.
+			for(std::size_t c = 0; c < number_of_samples; c++) {
+				++subdivider_;
+				if(subdivider_ == 28) {
+					++phase_;
+					subdivider_ = (phase_ & 15) ? 0 : -1;
+					if(phase_ == 65) phase_ = 0;
+
+					advance();
+				}
+
+				target[c] = level();
+			}
+		}
+
+	private:
+		int phase_ = 0;
+		int subdivider_ = 0;
+};
 
 }
 
 namespace Apple {
 namespace II {
 
-#define is_iie() ((model == Analyser::Static::AppleII::Target::Model::IIe) || (model == Analyser::Static::AppleII::Target::Model::EnhancedIIe))
-
-template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
+template <Analyser::Static::AppleII::Target::Model model, bool has_mockingboard> class ConcreteMachine:
 	public Apple::II::Machine,
 	public MachineTypes::TimedMachine,
 	public MachineTypes::ScanProducer,
@@ -83,14 +140,14 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			false>;
 		Processor m6502_;
 		VideoBusHandler video_bus_handler_;
-		Apple::II::Video::Video<VideoBusHandler, is_iie()> video_;
+		Apple::II::Video::Video<VideoBusHandler, is_iie(model)> video_;
 		int cycles_into_current_line_ = 0;
 		Cycles cycles_since_video_update_;
 
 		void update_video() {
 			video_.run_for(cycles_since_video_update_.flush<Cycles>());
 		}
-		static constexpr int audio_divider = 8;
+		static constexpr int audio_divider = has_mockingboard ? 1 : 8;
 		void update_audio() {
 			speaker_.run_for(audio_queue_, cycles_since_audio_update_.divide(Cycles(audio_divider)));
 		}
@@ -109,9 +166,23 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 		Concurrency::AsyncTaskQueue<false> audio_queue_;
 		Audio::Toggle audio_toggle_;
-		Outputs::Speaker::PullLowpass<Audio::Toggle> speaker_;
+		StretchedAYPair ays_;
+		using SourceT =
+			std::conditional_t<has_mockingboard, Outputs::Speaker::CompoundSource<StretchedAYPair, Audio::Toggle>, Audio::Toggle>;
+		using LowpassT = Outputs::Speaker::PullLowpass<SourceT>;
+
+		Outputs::Speaker::CompoundSource<StretchedAYPair, Audio::Toggle> mixer_;
+		Outputs::Speaker::PullLowpass<SourceT> speaker_;
 		Cycles cycles_since_audio_update_;
 
+		constexpr SourceT &lowpass_source() {
+			if constexpr (has_mockingboard) {
+				return mixer_;
+			} else {
+				return audio_toggle_;
+			}
+		}
+
 		// MARK: - Cards
 		static constexpr size_t NoActiveCard = 7;	// There is no 'card 0' in internal numbering.
 		size_t active_card_ = NoActiveCard;
@@ -155,6 +226,24 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			pick_card_messaging_group(card);
 		}
 
+		void card_did_change_interrupt_flags(Apple::II::Card *) final {
+			bool nmi = false;
+			bool irq = false;
+
+			for(const auto &card: cards_) {
+				if(card) {
+					nmi |= card->nmi();
+					irq |= card->irq();
+				}
+			}
+			m6502_.set_nmi_line(nmi);
+			m6502_.set_irq_line(irq);
+		}
+
+		Apple::II::Mockingboard *mockingboard() {
+			return dynamic_cast<Apple::II::Mockingboard *>(cards_[MockingboardSlot - 1].get());
+		}
+
 		Apple::II::DiskIICard *diskii_card() {
 			return dynamic_cast<Apple::II::DiskIICard *>(cards_[DiskIISlot - 1].get());
 		}
@@ -225,7 +314,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 				const auto zero_state = auxiliary_switches_.zero_state();
 
 				uint8_t *const ram = zero_state ? aux_ram_ : ram_;
-				uint8_t *const rom = is_iie() ? &rom_[3840] : rom_.data();
+				uint8_t *const rom = is_iie(model) ? &rom_[3840] : rom_.data();
 
 				// Which way the region here is mapped to be banks 1 and 2 is
 				// arbitrary.
@@ -286,7 +375,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			}
 
 			bool set_key_pressed(Key key, char value, bool is_pressed, bool is_repeat) final {
-				if constexpr (!is_iie()) {
+				if constexpr (!is_iie(model)) {
 					if(is_repeat && !repeat_is_pressed_) return true;
 				}
 
@@ -297,7 +386,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 					case Key::Down:			value = 0x0a;	break;
 					case Key::Up:			value = 0x0b;	break;
 					case Key::Backspace:
-						if(is_iie()) {
+						if(is_iie(model)) {
 							value = 0x7f;
 							break;
 						} else {
@@ -305,7 +394,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 						}
 					case Key::Enter:		value = 0x0d;	break;
 					case Key::Tab:
-						if (is_iie()) {
+						if (is_iie(model)) {
 							value = '\t';
 							break;
 						} else {
@@ -316,7 +405,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 					case Key::LeftOption:
 					case Key::RightMeta:
-						if (is_iie()) {
+						if (is_iie(model)) {
 							open_apple_is_pressed = is_pressed;
 							return true;
 						} else {
@@ -325,7 +414,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 					case Key::RightOption:
 					case Key::LeftMeta:
-						if (is_iie()) {
+						if (is_iie(model)) {
 							closed_apple_is_pressed = is_pressed;
 							return true;
 						} else {
@@ -346,7 +435,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 					case Key::F9:	case Key::F10:	case Key::F11:
 						repeat_is_pressed_ = is_pressed;
 
-						if constexpr (!is_iie()) {
+						if constexpr (!is_iie(model)) {
 							if(is_pressed && (!is_repeat || character_is_pressed_)) {
 								keyboard_input_ = uint8_t(last_pressed_character_ | 0x80);
 							}
@@ -374,12 +463,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 						}
 
 						// Prior to the IIe, the keyboard could produce uppercase only.
-						if(!is_iie()) value = char(toupper(value));
+						if(!is_iie(model)) value = char(toupper(value));
 
 						if(control_is_pressed_ && isalpha(value)) value &= 0xbf;
 
 						// TODO: properly map IIe keys
-						if(!is_iie() && shift_is_pressed_) {
+						if(!is_iie(model) && shift_is_pressed_) {
 							switch(value) {
 							case 0x27: value = 0x22; break; // ' -> "
 							case 0x2c: value = 0x3c; break; // , -> <
@@ -480,12 +569,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			video_bus_handler_(ram_, aux_ram_),
 			video_(video_bus_handler_),
 			audio_toggle_(audio_queue_),
-			speaker_(audio_toggle_),
+			ays_(audio_queue_),
+			mixer_(ays_, audio_toggle_),
+			speaker_(lowpass_source()),
 			language_card_(*this),
 			auxiliary_switches_(*this),
 			keyboard_(&m6502_) {
-			// The system's master clock rate.
-			constexpr float master_clock = 14318180.0;
 
 			// This is where things get slightly convoluted: establish the machine as having a clock rate
 			// equal to the number of cycles of work the 6502 will actually achieve. Which is less than
@@ -559,6 +648,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 				install_card(SCSISlot, new Apple::II::SCSICard(roms, int(master_clock / 14.0f)));
 			}
 
+			if(target.has_mockingboard) {
+				// The Mockingboard has a parasitic relationship with this class due to the way
+				// that audio outputs are implemented in this emulator.
+				install_card(MockingboardSlot, new Apple::II::Mockingboard(ays_));
+			}
+
 			rom_ = std::move(roms.find(system)->second);
 			// The IIe and Enhanced IIe ROMs often distributed are oversized; trim if necessary.
 			if(system == ROM::Name::AppleIIe || system == ROM::Name::AppleIIEnhancedE) {
@@ -629,7 +724,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 					if(write_pages_[address >> 8]) write_pages_[address >> 8][address & 0xff] = *value;
 				}
 
-				if(is_iie()) {
+				if(is_iie(model)) {
 					auxiliary_switches_.access(address, isReadOperation(operation));
 				}
 			} else {
@@ -669,7 +764,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 									*value &= 0x7f;
 									if(
 										joysticks_.button(0) ||
-										(is_iie() && keyboard_.open_apple_is_pressed)
+										(is_iie(model) && keyboard_.open_apple_is_pressed)
 									)
 										*value |= 0x80;
 								break;
@@ -677,7 +772,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 									*value &= 0x7f;
 									if(
 										joysticks_.button(1) ||
-										(is_iie() && keyboard_.closed_apple_is_pressed)
+										(is_iie(model) && keyboard_.closed_apple_is_pressed)
 									)
 										*value |= 0x80;
 								break;
@@ -699,7 +794,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 								} break;
 
 								// The IIe-only state reads follow...
-#define IIeSwitchRead(s)	*value = keyboard_.get_keyboard_input(); if(is_iie()) *value = (*value & 0x7f) | (s ? 0x80 : 0x00);
+#define IIeSwitchRead(s)	*value = keyboard_.get_keyboard_input(); if(is_iie(model)) *value = (*value & 0x7f) | (s ? 0x80 : 0x00);
 								case 0xc011:	IIeSwitchRead(language_card_.state().bank2);								break;
 								case 0xc012:	IIeSwitchRead(language_card_.state().read);									break;
 								case 0xc013:	IIeSwitchRead(auxiliary_switches_.switches().read_auxiliary_memory);		break;
@@ -718,12 +813,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 #undef IIeSwitchRead
 
 								case 0xc07f:
-									if(is_iie()) *value = (*value & 0x7f) | (video_.get_annunciator_3() ? 0x80 : 0x00);
+									if(is_iie(model)) *value = (*value & 0x7f) | (video_.get_annunciator_3() ? 0x80 : 0x00);
 								break;
 							}
 						} else {
 							// Write-only switches. All IIe as currently implemented.
-							if(is_iie()) {
+							if(is_iie(model)) {
 								auxiliary_switches_.access(address, false);
 								switch(address) {
 									default: break;
@@ -775,7 +870,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 					case 0xc05e:
 					case 0xc05f:
-						if(is_iie()) {
+						if(is_iie(model)) {
 							update_video();
 							video_.set_annunciator_3(!(address&1));
 						}
@@ -785,7 +880,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 						keyboard_.clear_keyboard_input();
 
 						// On the IIe, reading C010 returns additional key info.
-						if(is_iie() && isReadOperation(operation)) {
+						if(is_iie(model) && isReadOperation(operation)) {
 							*value = (keyboard_.get_key_is_down() ? 0x80 : 0x00) | (keyboard_.get_keyboard_input() & 0x7f);
 						}
 					break;
@@ -922,7 +1017,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 		}
 
 		bool prefers_logical_input() final {
-			return is_iie();
+			return is_iie(model);
 		}
 
 		Inputs::Keyboard &get_keyboard() final {
@@ -988,12 +1083,23 @@ using namespace Apple::II;
 std::unique_ptr<Machine> Machine::AppleII(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
 	using Target = Analyser::Static::AppleII::Target;
 	const Target *const appleii_target = dynamic_cast<const Target *>(target);
-	switch(appleii_target->model) {
-		default: return nullptr;
-		case Target::Model::II: return std::make_unique<ConcreteMachine<Target::Model::II>>(*appleii_target, rom_fetcher);
-		case Target::Model::IIplus: return std::make_unique<ConcreteMachine<Target::Model::IIplus>>(*appleii_target, rom_fetcher);
-		case Target::Model::IIe: return std::make_unique<ConcreteMachine<Target::Model::IIe>>(*appleii_target, rom_fetcher);
-		case Target::Model::EnhancedIIe: return std::make_unique<ConcreteMachine<Target::Model::EnhancedIIe>>(*appleii_target, rom_fetcher);
+
+	if(appleii_target->has_mockingboard) {
+		switch(appleii_target->model) {
+			default: return nullptr;
+			case Target::Model::II: return std::make_unique<ConcreteMachine<Target::Model::II, true>>(*appleii_target, rom_fetcher);
+			case Target::Model::IIplus: return std::make_unique<ConcreteMachine<Target::Model::IIplus, true>>(*appleii_target, rom_fetcher);
+			case Target::Model::IIe: return std::make_unique<ConcreteMachine<Target::Model::IIe, true>>(*appleii_target, rom_fetcher);
+			case Target::Model::EnhancedIIe: return std::make_unique<ConcreteMachine<Target::Model::EnhancedIIe, true>>(*appleii_target, rom_fetcher);
+		}
+	} else {
+		switch(appleii_target->model) {
+			default: return nullptr;
+			case Target::Model::II: return std::make_unique<ConcreteMachine<Target::Model::II, false>>(*appleii_target, rom_fetcher);
+			case Target::Model::IIplus: return std::make_unique<ConcreteMachine<Target::Model::IIplus, false>>(*appleii_target, rom_fetcher);
+			case Target::Model::IIe: return std::make_unique<ConcreteMachine<Target::Model::IIe, false>>(*appleii_target, rom_fetcher);
+			case Target::Model::EnhancedIIe: return std::make_unique<ConcreteMachine<Target::Model::EnhancedIIe, false>>(*appleii_target, rom_fetcher);
+		}
 	}
 }
 
diff --git a/Machines/Apple/AppleII/Card.hpp b/Machines/Apple/AppleII/Card.hpp
index a5b6f0afa..22c4411c5 100644
--- a/Machines/Apple/AppleII/Card.hpp
+++ b/Machines/Apple/AppleII/Card.hpp
@@ -49,12 +49,16 @@ class Card {
 									// by an access to $cfff.
 		};
 
+		// TODO: I think IO and Device are the wrong way around above.
+		// See https://retrocomputing.stackexchange.com/questions/5730/how-did-the-address-decode-for-apple-ii-expansion-cards-work
+		// and/or https://gglabs.us/sites/gglabs.us/files/a2scsi-A00_sch.pdf
+
 		/*!
 			Advances time by @c cycles, of which @c stretches were stretched.
 
 			This is posted only to cards that announced a select constraint. Cards with
 			no constraints, that want to be informed of every machine cycle, will receive
-			a call to perform_bus_operation every cycle and should use that for time keeping.
+			a call to @c perform_bus_operation every cycle and should use that for time keeping.
 		*/
 		virtual void run_for([[maybe_unused]] Cycles cycles, [[maybe_unused]] int stretches) {}
 
@@ -93,8 +97,15 @@ class Card {
 		/*! Cards may supply a target for activity observation if desired. */
 		virtual void set_activity_observer([[maybe_unused]] Activity::Observer *observer) {}
 
+		/// @returns The current semantic NMI line output of this card.
+		virtual bool nmi() { return false; }
+
+		/// @returns The current semantic IRQ line output of this card.
+		virtual bool irq() { return false; }
+
 		struct Delegate {
 			virtual void card_did_change_select_constraints(Card *card) = 0;
+			virtual void card_did_change_interrupt_flags(Card *card) = 0;
 		};
 		void set_delegate(Delegate *delegate) {
 			delegate_ = delegate;
diff --git a/Machines/Apple/AppleII/Mockingboard.hpp b/Machines/Apple/AppleII/Mockingboard.hpp
new file mode 100644
index 000000000..b7d98544c
--- /dev/null
+++ b/Machines/Apple/AppleII/Mockingboard.hpp
@@ -0,0 +1,135 @@
+//
+//  Mockingboard.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 14/02/2024.
+//  Copyright © 2024 Thomas Harte. All rights reserved.
+//
+
+#pragma once
+
+#include "Card.hpp"
+
+#include "../../../Components/6522/6522.hpp"
+
+namespace Apple::II {
+
+class AYPair {
+	public:
+		AYPair(Concurrency::AsyncTaskQueue<false> &queue) :
+			ays_{
+				{GI::AY38910::Personality::AY38910, queue},
+				{GI::AY38910::Personality::AY38910, queue},
+			} {}
+
+		void advance() {
+			ays_[0].advance();
+			ays_[1].advance();
+		}
+
+		void set_sample_volume_range(std::int16_t range) {
+			ays_[0].set_sample_volume_range(range);
+			ays_[1].set_sample_volume_range(range);
+		}
+
+		bool is_zero_level() const {
+			return ays_[0].is_zero_level() && ays_[1].is_zero_level();
+		}
+
+		Outputs::Speaker::StereoSample level() const {
+			Outputs::Speaker::StereoSample level;
+			level.left = ays_[0].level();
+			level.right = ays_[1].level();
+			return level;
+		}
+
+		GI::AY38910::AY38910SampleSource<false> &get(int index) {
+			return ays_[index];
+		}
+
+	private:
+		GI::AY38910::AY38910SampleSource<false> ays_[2];
+};
+
+class Mockingboard: public Card {
+	public:
+		Mockingboard(AYPair &ays) :
+			vias_{ {handlers_[0]}, {handlers_[1]} },
+			handlers_{ {*this, ays.get(0)}, {*this, ays.get(1)}} {
+			set_select_constraints(0);
+		}
+
+		void perform_bus_operation(Select select, bool is_read, uint16_t address, uint8_t *value) final {
+			if(!(select & Device)) {
+				return;
+			}
+
+			int index = (address >> 7) & 1;
+			if(is_read) {
+				*value = vias_[index].read(address);
+			} else {
+				vias_[index].write(address, *value);
+			}
+		}
+
+		void run_for(Cycles cycles, int) final {
+			vias_[0].run_for(cycles);
+			vias_[1].run_for(cycles);
+		}
+
+		bool nmi() final {
+			return handlers_[1].interrupt;
+		}
+
+		bool irq() final {
+			return handlers_[0].interrupt;
+		}
+
+		void did_change_interrupt_flags() {
+			delegate_->card_did_change_interrupt_flags(this);
+		}
+
+	private:
+		struct AYVIA: public MOS::MOS6522::PortHandler {
+			AYVIA(Mockingboard &card, GI::AY38910::AY38910SampleSource<false> &ay) :
+				card(card), ay(ay) {}
+
+			void set_interrupt_status(bool status) {
+				interrupt = status;
+				card.did_change_interrupt_flags();
+			}
+
+			void set_port_output(MOS::MOS6522::Port port, uint8_t value, uint8_t) {
+				if(port) {
+					using ControlLines = GI::AY38910::ControlLines;
+					ay.set_control_lines(
+						ControlLines(
+							((value & 1) ? ControlLines::BC1 : 0) |
+							((value & 2) ? ControlLines::BDIR : 0) |
+							ControlLines::BC2
+						)
+					);
+
+					ay.set_reset(!(value & 4));
+				} else {
+					ay.set_data_input(value);
+				}
+			}
+
+			uint8_t get_port_input(MOS::MOS6522::Port port) {
+				if(!port) {
+					return ay.get_data_output();
+				}
+				return 0xff;
+			}
+
+			bool interrupt;
+			Mockingboard &card;
+			GI::AY38910::AY38910SampleSource<false> &ay;
+		};
+
+		MOS::MOS6522::MOS6522<AYVIA> vias_[2];
+		AYVIA handlers_[2];
+};
+
+}
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 3babbde3e..069031998 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -1568,6 +1568,7 @@
 		4B71368D1F788112008B8ED9 /* Parser.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Parser.hpp; sourceTree = "<group>"; };
 		4B71368F1F789C93008B8ED9 /* SegmentParser.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = SegmentParser.cpp; sourceTree = "<group>"; };
 		4B7136901F789C93008B8ED9 /* SegmentParser.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = SegmentParser.hpp; sourceTree = "<group>"; };
+		4B72FAEF2B7D51BB000C7E90 /* Mockingboard.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Mockingboard.hpp; sourceTree = "<group>"; };
 		4B74CF7F2312FA9C00500CE8 /* HFV.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = HFV.hpp; sourceTree = "<group>"; };
 		4B74CF802312FA9C00500CE8 /* HFV.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = HFV.cpp; sourceTree = "<group>"; };
 		4B75F978280D7C5100121055 /* 68000DecoderTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = 68000DecoderTests.mm; sourceTree = "<group>"; };
@@ -4840,6 +4841,7 @@
 				4B2E86E125DC95150024F1E9 /* Joystick.hpp */,
 				4BF40A5525424C770033EA39 /* LanguageCardSwitches.hpp */,
 				4BE0151C286A8C8E00EA42E9 /* MemorySwitches.hpp */,
+				4B72FAEF2B7D51BB000C7E90 /* Mockingboard.hpp */,
 				4B4C81C428B3C5CD00F84AE9 /* SCSICard.hpp */,
 				4BCE004F227CE8CA000CA200 /* Video.hpp */,
 				4B8DF4F2254E141700F3433C /* VideoSwitches.hpp */,
diff --git a/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.h b/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.h
index 1df0c77b7..e7f863ba9 100644
--- a/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.h	
+++ b/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.h	
@@ -141,7 +141,7 @@ typedef int Kilobytes;
 
 - (instancetype)initWithAmigaModel:(CSMachineAmigaModel)model chipMemorySize:(Kilobytes)chipMemorySize fastMemorySize:(Kilobytes)fastMemorySize;
 - (instancetype)initWithAmstradCPCModel:(CSMachineCPCModel)model;
-- (instancetype)initWithAppleIIModel:(CSMachineAppleIIModel)model diskController:(CSMachineAppleIIDiskController)diskController;
+- (instancetype)initWithAppleIIModel:(CSMachineAppleIIModel)model diskController:(CSMachineAppleIIDiskController)diskController hasMockingboard:(BOOL)hasMockingboard;
 - (instancetype)initWithAppleIIgsModel:(CSMachineAppleIIgsModel)model memorySize:(Kilobytes)memorySize;
 - (instancetype)initWithAtariSTModel:(CSMachineAtariSTModel)model memorySize:(Kilobytes)memorySize;
 - (instancetype)initWithElectronDFS:(BOOL)dfs adfs:(BOOL)adfs ap6:(BOOL)ap6 sidewaysRAM:(BOOL)sidewaysRAM;
diff --git a/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm b/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm
index 9bdcc1f9e..f825e844f 100644
--- a/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm	
@@ -93,7 +93,7 @@
 	return self;
 }
 
-- (instancetype)initWithAppleIIModel:(CSMachineAppleIIModel)model diskController:(CSMachineAppleIIDiskController)diskController {
+- (instancetype)initWithAppleIIModel:(CSMachineAppleIIModel)model diskController:(CSMachineAppleIIDiskController)diskController hasMockingboard:(BOOL)hasMockingboard {
 	self = [super init];
 	if(self) {
 		using Target = Analyser::Static::AppleII::Target;
@@ -110,6 +110,7 @@
 			case CSMachineAppleIIDiskControllerSixteenSector:	target->disk_controller = Target::DiskController::SixteenSector;	break;
 			case CSMachineAppleIIDiskControllerThirteenSector:	target->disk_controller = Target::DiskController::ThirteenSector;	break;
 		}
+		target->has_mockingboard = hasMockingboard;
 		_targets.push_back(std::move(target));
 	}
 	return self;
diff --git a/OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib b/OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib
index 7b53dd6f6..b445ea9eb 100644
--- a/OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib	
+++ b/OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib	
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="21701" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="22505" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="21701"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="22505"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -18,7 +18,7 @@
             <windowStyleMask key="styleMask" titled="YES" documentModal="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
             <rect key="contentRect" x="196" y="240" width="590" height="369"/>
-            <rect key="screenRect" x="0.0" y="0.0" width="1800" height="1131"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1440"/>
             <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
                 <rect key="frame" x="0.0" y="0.0" width="590" height="369"/>
                 <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
@@ -49,7 +49,7 @@ Gw
                             <action selector="cancelCreateMachine:" target="-2" id="lf8-PM-c0m"/>
                         </connections>
                     </button>
-                    <textField horizontalHuggingPriority="1" verticalHuggingPriority="1" horizontalCompressionResistancePriority="250" setsMaxLayoutWidthAtFirstLayout="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9YM-5x-pc0">
+                    <textField focusRingType="none" horizontalHuggingPriority="1" verticalHuggingPriority="1" horizontalCompressionResistancePriority="250" setsMaxLayoutWidthAtFirstLayout="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9YM-5x-pc0">
                         <rect key="frame" x="18" y="14" width="405" height="32"/>
                         <textFieldCell key="cell" allowsUndo="NO" sendsActionOnEndEditing="YES" id="xTm-Oy-oz5">
                             <font key="font" metaFont="system"/>
@@ -104,7 +104,7 @@ Gw
                             <autoresizingMask key="autoresizingMask"/>
                         </scroller>
                     </scrollView>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="VAc-6N-O7q">
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="VAc-6N-O7q">
                         <rect key="frame" x="18" y="328" width="554" height="21"/>
                         <textFieldCell key="cell" lineBreakMode="clipping" title="Choose a machine" id="32m-Vs-dPO">
                             <font key="font" textStyle="title2" name=".SFNS-Regular"/>
@@ -135,7 +135,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="P6K-dt-stj">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="P6K-dt-stj">
                                             <rect key="frame" x="18" y="216" width="89" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Chip Memory:" id="FIO-ZR-rsA">
                                                 <font key="font" metaFont="system"/>
@@ -143,7 +143,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="YD0-OJ-2bY">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="YD0-OJ-2bY">
                                             <rect key="frame" x="18" y="186" width="87" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Fast Memory:" id="Rpz-39-jyt">
                                                 <font key="font" metaFont="system"/>
@@ -202,7 +202,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="c3g-96-b3x">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="c3g-96-b3x">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="53v-92-jmf">
                                                 <font key="font" metaFont="system"/>
@@ -223,19 +223,19 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="Apple II" identifier="appleii" id="P59-QG-LOa">
                                 <view key="view" id="dHz-Yv-GNq">
-                                    <rect key="frame" x="10" y="7" width="400" height="222"/>
+                                    <rect key="frame" x="10" y="7" width="400" height="254"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="V5Z-dX-Ns4">
-                                            <rect key="frame" x="18" y="184" width="46" height="16"/>
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="V5Z-dX-Ns4">
+                                            <rect key="frame" x="18" y="216" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="qV3-2P-3JW">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="WnO-ef-IC6">
-                                            <rect key="frame" x="18" y="154" width="96" height="16"/>
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="WnO-ef-IC6">
+                                            <rect key="frame" x="18" y="186" width="98" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Disk Controller:" id="kbf-rc-Y4M">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@@ -243,7 +243,7 @@ Gw
                                             </textFieldCell>
                                         </textField>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="jli-ac-Sij">
-                                            <rect key="frame" x="67" y="178" width="117" height="25"/>
+                                            <rect key="frame" x="67" y="210" width="117" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Apple II" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="axesIndependently" inset="2" selectedItem="VBQ-JG-AeM" id="U6V-us-O2F">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -258,7 +258,7 @@ Gw
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LSB-WP-FMi">
-                                            <rect key="frame" x="117" y="148" width="134" height="25"/>
+                                            <rect key="frame" x="119" y="180" width="134" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Sixteen Sector" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="16" imageScaling="axesIndependently" inset="2" selectedItem="QaV-Yr-k9o" id="8BT-RV-2Nm">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -271,16 +271,25 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
+                                        <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="6UC-5k-3b6">
+                                            <rect key="frame" x="18" y="159" width="140" height="18"/>
+                                            <buttonCell key="cell" type="check" title="Has Mockingboard" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="vpo-D2-Tzo">
+                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                                                <font key="font" metaFont="system"/>
+                                            </buttonCell>
+                                        </button>
                                     </subviews>
                                     <constraints>
                                         <constraint firstItem="WnO-ef-IC6" firstAttribute="leading" secondItem="dHz-Yv-GNq" secondAttribute="leading" constant="20" symbolic="YES" id="5RF-1w-9HW"/>
-                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="LSB-WP-FMi" secondAttribute="bottom" constant="20" symbolic="YES" id="865-cv-qVk"/>
+                                        <constraint firstItem="6UC-5k-3b6" firstAttribute="top" secondItem="LSB-WP-FMi" secondAttribute="bottom" constant="8" symbolic="YES" id="5Wg-y8-hWt"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="LSB-WP-FMi" secondAttribute="trailing" constant="20" symbolic="YES" id="9GL-al-1qi"/>
                                         <constraint firstItem="WnO-ef-IC6" firstAttribute="centerY" secondItem="LSB-WP-FMi" secondAttribute="centerY" id="Fuj-zT-MIm"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="jli-ac-Sij" secondAttribute="trailing" constant="20" symbolic="YES" id="I8d-OR-ICN"/>
                                         <constraint firstItem="jli-ac-Sij" firstAttribute="top" secondItem="dHz-Yv-GNq" secondAttribute="top" constant="20" symbolic="YES" id="Qi1-CV-A0c"/>
                                         <constraint firstItem="V5Z-dX-Ns4" firstAttribute="leading" secondItem="dHz-Yv-GNq" secondAttribute="leading" constant="20" symbolic="YES" id="SWc-iX-1We"/>
+                                        <constraint firstItem="6UC-5k-3b6" firstAttribute="leading" secondItem="dHz-Yv-GNq" secondAttribute="leading" constant="20" symbolic="YES" id="VRC-Bl-5gF"/>
                                         <constraint firstItem="LSB-WP-FMi" firstAttribute="leading" secondItem="WnO-ef-IC6" secondAttribute="trailing" constant="8" symbolic="YES" id="bte-XA-xNQ"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="6UC-5k-3b6" secondAttribute="bottom" constant="20" symbolic="YES" id="iTH-2B-JJa"/>
                                         <constraint firstItem="LSB-WP-FMi" firstAttribute="top" secondItem="jli-ac-Sij" secondAttribute="bottom" constant="10" symbolic="YES" id="ki5-JR-vRe"/>
                                         <constraint firstItem="jli-ac-Sij" firstAttribute="leading" secondItem="V5Z-dX-Ns4" secondAttribute="trailing" constant="8" symbolic="YES" id="qcd-pf-0T3"/>
                                         <constraint firstItem="V5Z-dX-Ns4" firstAttribute="centerY" secondItem="jli-ac-Sij" secondAttribute="centerY" id="v25-BK-BoD"/>
@@ -292,7 +301,7 @@ Gw
                                     <rect key="frame" x="10" y="7" width="400" height="222"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0d9-IG-gKU">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0d9-IG-gKU">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="kiv-1P-FWc">
                                                 <font key="font" metaFont="system"/>
@@ -300,7 +309,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LES-76-Ovz">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="LES-76-Ovz">
                                             <rect key="frame" x="18" y="154" width="85" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="OLJ-nC-yyj">
                                                 <font key="font" metaFont="system"/>
@@ -357,7 +366,7 @@ Gw
                                     <rect key="frame" x="10" y="7" width="400" height="222"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dKg-qC-BBF">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dKg-qC-BBF">
                                             <rect key="frame" x="18" y="184" width="58" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory:" id="ZBF-0r-RNK">
                                                 <font key="font" metaFont="system"/>
@@ -515,7 +524,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ykc-W1-YaS">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ykc-W1-YaS">
                                             <rect key="frame" x="18" y="124" width="43" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="EXOS:" id="gUC-PN-zVL">
                                                 <font key="font" metaFont="system"/>
@@ -523,7 +532,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="frx-nk-c3P">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="frx-nk-c3P">
                                             <rect key="frame" x="18" y="184" width="59" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Machine:" id="uTv-hH-mIC">
                                                 <font key="font" metaFont="system"/>
@@ -531,7 +540,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dzd-tH-BjX">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dzd-tH-BjX">
                                             <rect key="frame" x="18" y="94" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="BASIC:" id="ai1-oR-X6Y">
                                                 <font key="font" metaFont="system"/>
@@ -539,7 +548,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="pxr-Bq-yh0">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="pxr-Bq-yh0">
                                             <rect key="frame" x="18" y="64" width="36" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="DOS:" id="NFk-cp-DfS">
                                                 <font key="font" metaFont="system"/>
@@ -547,7 +556,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="rHr-bh-QMV">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="rHr-bh-QMV">
                                             <rect key="frame" x="17" y="154" width="47" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Speed:" id="sAw-C9-Sf7">
                                                 <font key="font" metaFont="system"/>
@@ -593,7 +602,7 @@ Gw
                                     <rect key="frame" x="10" y="7" width="400" height="222"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZOY-4E-Cfl">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZOY-4E-Cfl">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="h9r-i6-66j">
                                                 <font key="font" metaFont="system"/>
@@ -653,7 +662,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZaD-7v-rMS">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZaD-7v-rMS">
                                             <rect key="frame" x="18" y="154" width="50" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Region:" id="x4m-eh-Nif">
                                                 <font key="font" metaFont="system"/>
@@ -661,7 +670,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gFV-RB-7dB">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gFV-RB-7dB">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="r7C-zE-gyj">
                                                 <font key="font" metaFont="system"/>
@@ -716,7 +725,7 @@ Gw
                                     <rect key="frame" x="10" y="7" width="400" height="222"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0ct-tf-uRH">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0ct-tf-uRH">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="Xm1-7x-YVl">
                                                 <font key="font" metaFont="system"/>
@@ -754,7 +763,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="okM-ZI-NbF">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="okM-ZI-NbF">
                                             <rect key="frame" x="18" y="154" width="92" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Disk Interface:" id="SFK-hS-tFC">
                                                 <font key="font" metaFont="system"/>
@@ -796,7 +805,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="uhf-1k-ibT">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="uhf-1k-ibT">
                                             <rect key="frame" x="18" y="198" width="95" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Video Adaptor:" id="ROV-EU-T3W">
                                                 <font key="font" metaFont="system"/>
@@ -804,7 +813,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8vF-eu-ClP">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8vF-eu-ClP">
                                             <rect key="frame" x="18" y="168" width="47" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Speed:" id="qXc-wf-5jm">
                                                 <font key="font" metaFont="system"/>
@@ -876,7 +885,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="MTh-9p-FqC">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="MTh-9p-FqC">
                                             <rect key="frame" x="18" y="184" width="50" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Region:" id="F3g-Ya-ypU">
                                                 <font key="font" metaFont="system"/>
@@ -884,7 +893,7 @@ Gw
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gRS-DK-rIy">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="gRS-DK-rIy">
                                             <rect key="frame" x="18" y="154" width="87" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="a4I-vG-yCp">
                                                 <font key="font" metaFont="system"/>
@@ -937,7 +946,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="NCX-4e-lSu">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="NCX-4e-lSu">
                                             <rect key="frame" x="18" y="184" width="87" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="e6x-TE-OC5">
                                                 <font key="font" metaFont="system"/>
@@ -985,7 +994,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8tU-73-XEE">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8tU-73-XEE">
                                             <rect key="frame" x="18" y="184" width="87" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="z4b-oR-Yl2">
                                                 <font key="font" metaFont="system"/>
@@ -1026,7 +1035,7 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
-                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="fJ3-ma-Byy">
+                                        <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="fJ3-ma-Byy">
                                             <rect key="frame" x="18" y="184" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="JId-Tp-LrE">
                                                 <font key="font" metaFont="system"/>
@@ -1075,6 +1084,7 @@ Gw
                 <outlet property="amigaChipRAMButton" destination="qfH-1l-GXp" id="3PG-QC-tyI"/>
                 <outlet property="amigaFastRAMButton" destination="af8-pF-qc9" id="laa-1H-JfD"/>
                 <outlet property="appleIIDiskControllerButton" destination="LSB-WP-FMi" id="Ssa-jd-t63"/>
+                <outlet property="appleIIMockingboardButton" destination="6UC-5k-3b6" id="1h1-bx-edx"/>
                 <outlet property="appleIIModelButton" destination="jli-ac-Sij" id="Jm3-f7-C17"/>
                 <outlet property="appleIIgsMemorySizeButton" destination="nQa-YS-utT" id="pTV-XL-zX3"/>
                 <outlet property="appleIIgsModelButton" destination="gcS-uy-mzl" id="Jcc-jC-cV1"/>
diff --git a/OSBindings/Mac/Clock Signal/MachinePicker/MachinePicker.swift b/OSBindings/Mac/Clock Signal/MachinePicker/MachinePicker.swift
index d9afc3431..a9217dba3 100644
--- a/OSBindings/Mac/Clock Signal/MachinePicker/MachinePicker.swift	
+++ b/OSBindings/Mac/Clock Signal/MachinePicker/MachinePicker.swift	
@@ -26,6 +26,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 	// MARK: - Apple II properties
 	@IBOutlet var appleIIModelButton: NSPopUpButton!
 	@IBOutlet var appleIIDiskControllerButton: NSPopUpButton!
+	@IBOutlet var appleIIMockingboardButton: NSButton!
 
 	// MARK: - Apple IIgs properties
 	@IBOutlet var appleIIgsModelButton: NSPopUpButton!
@@ -117,6 +118,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 		// Apple II settings
 		appleIIModelButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.appleIIModel"))
 		appleIIDiskControllerButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.appleIIDiskController"))
+		appleIIMockingboardButton.state = standardUserDefaults.bool(forKey: "new.appleIIMockingboard") ? .on : .off
 
 		// Apple IIgs settings
 		appleIIgsModelButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.appleIIgsModel"))
@@ -187,6 +189,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 		// Apple II settings
 		standardUserDefaults.set(appleIIModelButton.selectedTag(), forKey: "new.appleIIModel")
 		standardUserDefaults.set(appleIIDiskControllerButton.selectedTag(), forKey: "new.appleIIDiskController")
+		standardUserDefaults.set(appleIIMockingboardButton.state == .on, forKey: "new.appleIIMockingboard")
 
 		// Apple IIgs settings
 		standardUserDefaults.set(appleIIgsModelButton.selectedTag(), forKey: "new.appleIIgsModel")
@@ -292,7 +295,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 					default:	diskController = .none
 				}
 
-				return CSStaticAnalyser(appleIIModel: model, diskController: diskController)
+				return CSStaticAnalyser(appleIIModel: model, diskController: diskController, hasMockingboard: appleIIMockingboardButton.state == .on)
 
 			case "appleiigs":
 				var model: CSMachineAppleIIgsModel = .ROM00
diff --git a/OSBindings/Qt/mainwindow.cpp b/OSBindings/Qt/mainwindow.cpp
index 37080d954..e21fc48ac 100644
--- a/OSBindings/Qt/mainwindow.cpp
+++ b/OSBindings/Qt/mainwindow.cpp
@@ -1042,6 +1042,8 @@ void MainWindow::start_appleII() {
 		case 2:		target->disk_controller = Target::DiskController::None;				break;
 	}
 
+	target->has_mockingboard = ui->appleIIMockingboardCheckBox->isChecked();
+
 	launchTarget(std::move(target));
 }
 
diff --git a/OSBindings/Qt/mainwindow.ui b/OSBindings/Qt/mainwindow.ui
index eac216907..82ad39f93 100644
--- a/OSBindings/Qt/mainwindow.ui
+++ b/OSBindings/Qt/mainwindow.ui
@@ -202,6 +202,13 @@
           </item>
          </layout>
         </item>
+        <item>
+         <widget class="QCheckBox" name="appleIIMockingboardCheckBox">
+          <property name="text">
+           <string>Has Mockingboard</string>
+          </property>
+         </widget>
+        </item>
        </layout>
       </widget>
       <widget class="QWidget" name="appleIIgsTab">
diff --git a/Outputs/Speaker/Implementation/CompoundSource.hpp b/Outputs/Speaker/Implementation/CompoundSource.hpp
index bdfe93545..2cafa10c7 100644
--- a/Outputs/Speaker/Implementation/CompoundSource.hpp
+++ b/Outputs/Speaker/Implementation/CompoundSource.hpp
@@ -77,29 +77,28 @@ template <typename... T> class CompoundSource:
 
 						// Map up and return.
 						for(std::size_t c = 0; c < number_of_samples; c++) {
-							Outputs::Speaker::apply<action>(target[c].left, StereoSample(conversion_source_[c]));
+							Outputs::Speaker::apply<action>(target[c], StereoSample(conversion_source_[c]));
 						}
-						return;
-					}
+					} else {
+						constexpr bool is_final_source = sizeof...(R) == 0;
 
-					constexpr bool is_final_source = sizeof...(R) == 0;
-
-					// Get the rest of the output, if any.
-					if constexpr (!is_final_source) {
-						next_source_.template apply_samples<action, output_stereo>(number_of_samples, target);
-					}
-
-					if(source_.is_zero_level()) {
-						// This component is currently outputting silence; therefore don't add anything to the output
-						// audio. Zero fill only if this is the final source (as everything above will be additive).
-						if constexpr (is_final_source) {
-							Outputs::Speaker::fill<action>(target, target + number_of_samples, typename SampleT<output_stereo>::type());
+						// Get the rest of the output, if any.
+						if constexpr (!is_final_source) {
+							next_source_.template apply_samples<action, output_stereo>(number_of_samples, target);
 						}
-						return;
-					}
 
-					// Add in this component's output.
-					source_.template apply_samples<is_final_source ? Action::Store : Action::Mix>(number_of_samples, target);
+						if(source_.is_zero_level()) {
+							// This component is currently outputting silence; therefore don't add anything to the output
+							// audio. Zero fill only if this is the final source (as everything above will be additive).
+							if constexpr (is_final_source) {
+								Outputs::Speaker::fill<action>(target, target + number_of_samples, typename SampleT<output_stereo>::type());
+							}
+							return;
+						}
+
+						// Add in this component's output.
+						source_.template apply_samples<is_final_source ? Action::Store : Action::Mix>(number_of_samples, target);
+					}
 				}
 
 				void set_scaled_volume_range(int16_t range, double *volumes, double scale) {