diff --git a/build.sh b/build.sh
index de4d9f1..ef9ce68 100755
--- a/build.sh
+++ b/build.sh
@@ -18,9 +18,6 @@ fi
 cd circle-stdlib/
 make mrproper || true
 ./configure -r ${RPI} --prefix "${TOOLCHAIN_PREFIX}"
-if [ "${RPI}" -gt "1" ]; then
-    echo "DEFINE += -DARM_ALLOW_MULTI_CORE" >> libs/circle/Config.mk
-fi
 echo "DEFINE += -DUSE_PWM_AUDIO_ON_ZERO" >> libs/circle/Config.mk
 echo "DEFINE += -DSAVE_VFP_REGS_ON_IRQ" >> libs/circle/Config.mk
 echo "DEFINE += -DREALTIME" >> libs/circle/Config.mk
diff --git a/src/kernel.cpp b/src/kernel.cpp
index dde24f0..2ad706d 100644
--- a/src/kernel.cpp
+++ b/src/kernel.cpp
@@ -18,6 +18,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //
 #include "kernel.h"
+#include <string.h>
 #include <circle/logger.h>
 #include <circle/synchronize.h>
 #include <assert.h>
@@ -64,7 +65,27 @@ bool CKernel::Initialize (void)
 
 	m_Config.Load ();
 
-	m_pDexed = new CMiniDexed (&m_Config, &mInterrupt, &m_GPIOManager, &m_I2CMaster);
+	// select the sound device
+	const char *pSoundDevice = m_Config.GetSoundDevice ();
+	if (strcmp (pSoundDevice, "i2s") == 0)
+	{
+		LOGNOTE ("I2S mode");
+
+		m_pDexed = new CMiniDexedI2S (&m_Config, &mInterrupt, &m_GPIOManager, &m_I2CMaster);
+	}
+	else if (strcmp (pSoundDevice, "hdmi") == 0)
+	{
+		LOGNOTE ("HDMI mode");
+
+		m_pDexed = new CMiniDexedHDMI (&m_Config, &mInterrupt, &m_GPIOManager);
+	}
+	else
+	{
+		LOGNOTE ("PWM mode");
+
+		m_pDexed = new CMiniDexedPWM (&m_Config, &mInterrupt, &m_GPIOManager);
+	}
+
 	assert (m_pDexed);
 
 	if (!m_pDexed->Initialize ())
diff --git a/src/minidexed.cpp b/src/minidexed.cpp
index 23f64cb..476a8f3 100644
--- a/src/minidexed.cpp
+++ b/src/minidexed.cpp
@@ -19,28 +19,18 @@
 //
 #include "minidexed.h"
 #include <circle/logger.h>
-#include <circle/memory.h>
-#include <circle/pwmsoundbasedevice.h>
-#include <circle/i2ssoundbasedevice.h>
-#include <circle/hdmisoundbasedevice.h>
-#include <string.h>
 #include <stdio.h>
 #include <assert.h>
 
 LOGMODULE ("minidexed");
 
-CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
-			CGPIOManager *pGPIOManager, CI2CMaster *pI2CMaster)
+CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt, CGPIOManager *pGPIOManager)
 :	CDexedAdapter (CConfig::MaxNotes, pConfig->GetSampleRate ()),
-#ifdef ARM_ALLOW_MULTI_CORE
-	CMultiCoreSupport (CMemorySystem::Get ()),
-#endif
 	m_pConfig (pConfig),
 	m_UI (this, pGPIOManager, pConfig),
 	m_PCKeyboard (this),
 	m_SerialMIDI (this, pInterrupt, pConfig),
 	m_bUseSerial (false),
-	m_pSoundDevice (0),
 	m_GetChunkTimer ("GetChunk",
 			 1000000U * pConfig->GetChunkSize ()/2 / pConfig->GetSampleRate ()),
 	m_bProfileEnabled (m_pConfig->GetProfileEnabled ())
@@ -50,38 +40,10 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
 		m_pMIDIKeyboard[i] = new CMIDIKeyboard (this, pConfig, i);
 		assert (m_pMIDIKeyboard[i]);
 	}
-
-	// select the sound device
-	const char *pDeviceName = pConfig->GetSoundDevice ();
-	if (strcmp (pDeviceName, "i2s") == 0)
-	{
-		LOGNOTE ("I2S mode");
-
-		m_pSoundDevice = new CI2SSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
-							  pConfig->GetChunkSize (), false,
-							  pI2CMaster, pConfig->GetDACI2CAddress ());
-	}
-	else if (strcmp (pDeviceName, "hdmi") == 0)
-	{
-		LOGNOTE ("HDMI mode");
-
-		m_pSoundDevice = new CHDMISoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
-							   pConfig->GetChunkSize ());
-	}
-	else
-	{
-		LOGNOTE ("PWM mode");
-
-		m_pSoundDevice = new CPWMSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
-							  pConfig->GetChunkSize ());
-	}
 };
 
 bool CMiniDexed::Initialize (void)
 {
-	assert (m_pConfig);
-	assert (m_pSoundDevice);
-
 	if (!m_UI.Initialize ())
 	{
 		return false;
@@ -101,37 +63,11 @@ bool CMiniDexed::Initialize (void)
 	ProgramChange (0);
 	setTranspose (24);
 
-	// setup and start the sound device
-	if (!m_pSoundDevice->AllocateQueueFrames (m_pConfig->GetChunkSize ()/2))
-	{
-		LOGERR ("Cannot allocate sound queue");
-
-		return false;
-	}
-
-	m_pSoundDevice->SetWriteFormat (SoundFormatSigned16, 1);	// 16-bit Mono
-
-	m_nQueueSizeFrames = m_pSoundDevice->GetQueueSizeFrames ();
-
-	m_pSoundDevice->Start ();
-
-#ifdef ARM_ALLOW_MULTI_CORE
-	// start secondary cores
-	if (!CMultiCoreSupport::Initialize ())
-	{
-		return false;
-	}
-#endif
-
 	return true;
 }
 
 void CMiniDexed::Process (bool bPlugAndPlayUpdated)
 {
-#ifndef ARM_ALLOW_MULTI_CORE
-	ProcessSound ();
-#endif
-
 	for (unsigned i = 0; i < CConfig::MaxUSBMIDIDevices; i++)
 	{
 		assert (m_pMIDIKeyboard[i]);
@@ -153,21 +89,6 @@ void CMiniDexed::Process (bool bPlugAndPlayUpdated)
 	}
 }
 
-#ifdef ARM_ALLOW_MULTI_CORE
-
-void CMiniDexed::Run (unsigned nCore)
-{
-	if (nCore == 1)
-	{
-		while (1)
-		{
-			ProcessSound ();
-		}
-	}
-}
-
-#endif
-
 CSysExFileLoader *CMiniDexed::GetSysExFileLoader (void)
 {
 	return &m_SysExFileLoader;
@@ -199,30 +120,159 @@ void CMiniDexed::ProgramChange (unsigned nProgram)
 	m_UI.ProgramChanged (nProgram);
 }
 
-void CMiniDexed::ProcessSound (void)
+//// PWM //////////////////////////////////////////////////////////////////////
+
+CMiniDexedPWM::CMiniDexedPWM (CConfig *pConfig, CInterruptSystem *pInterrupt,
+			      CGPIOManager *pGPIOManager)
+:	CMiniDexed (pConfig, pInterrupt, pGPIOManager),
+	CPWMSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
+			     pConfig->GetChunkSize ())
 {
-	assert (m_pSoundDevice);
+}
 
-	unsigned nFrames = m_nQueueSizeFrames - m_pSoundDevice->GetQueueFramesAvail ();
-	if (nFrames >= m_nQueueSizeFrames/2)
+bool CMiniDexedPWM::Initialize (void)
+{
+	if (!CMiniDexed::Initialize ())
 	{
-		if (m_bProfileEnabled)
-		{
-			m_GetChunkTimer.Start ();
-		}
+		return false;
+	}
 
-		int16_t SampleBuffer[nFrames];
-		getSamples (nFrames, SampleBuffer);
+	return Start ();
+}
 
-		if (   m_pSoundDevice->Write (SampleBuffer, sizeof SampleBuffer)
-		    != (int) sizeof SampleBuffer)
-		{
-			LOGERR ("Sound data dropped");
-		}
+unsigned CMiniDexedPWM::GetChunk (u32 *pBuffer, unsigned nChunkSize)
+{
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Start ();
+	}
+
+	unsigned nResult = nChunkSize;
+
+	int16_t SampleBuffer[nChunkSize/2];
+	getSamples (nChunkSize/2, SampleBuffer);
+
+	for (unsigned i = 0; nChunkSize > 0; nChunkSize -= 2)	// fill the whole buffer
+	{
+		s32 nSample = SampleBuffer[i++];
+		nSample += 32768;
+		nSample *= GetRangeMax()/2;
+		nSample /= 32768;
 
-		if (m_bProfileEnabled)
+		*pBuffer++ = nSample;		// 2 stereo channels
+		*pBuffer++ = nSample;
+	}
+
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Stop ();
+	}
+
+	return nResult;
+};
+
+//// I2S //////////////////////////////////////////////////////////////////////
+
+CMiniDexedI2S::CMiniDexedI2S (CConfig *pConfig, CInterruptSystem *pInterrupt,
+			      CGPIOManager *pGPIOManager, CI2CMaster *pI2CMaster)
+:	CMiniDexed (pConfig, pInterrupt, pGPIOManager),
+	CI2SSoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
+			     pConfig->GetChunkSize (), false, pI2CMaster,
+			     pConfig->GetDACI2CAddress ())
+{
+}
+
+bool CMiniDexedI2S::Initialize (void)
+{
+	if (!CMiniDexed::Initialize ())
+	{
+		return false;
+	}
+
+	return Start ();
+}
+
+unsigned CMiniDexedI2S::GetChunk (u32 *pBuffer, unsigned nChunkSize)
+{
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Start ();
+	}
+
+	unsigned nResult = nChunkSize;
+
+	int16_t SampleBuffer[nChunkSize/2];
+	getSamples (nChunkSize/2, SampleBuffer);
+
+	for (unsigned i = 0; nChunkSize > 0; nChunkSize -= 2)	// fill the whole buffer
+	{
+		s32 nSample = SampleBuffer[i++];
+		nSample <<= 8;
+
+		*pBuffer++ = nSample;		// 2 stereo channels
+		*pBuffer++ = nSample;
+	}
+
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Stop ();
+	}
+
+	return nResult;
+};
+
+//// HDMI /////////////////////////////////////////////////////////////////////
+
+CMiniDexedHDMI::CMiniDexedHDMI (CConfig *pConfig, CInterruptSystem *pInterrupt,
+				CGPIOManager *pGPIOManager)
+:	CMiniDexed (pConfig, pInterrupt, pGPIOManager),
+	CHDMISoundBaseDevice (pInterrupt, pConfig->GetSampleRate (),
+			      pConfig->GetChunkSize ())
+{
+}
+
+bool CMiniDexedHDMI::Initialize (void)
+{
+	if (!CMiniDexed::Initialize ())
+	{
+		return false;
+	}
+
+	return Start ();
+}
+
+unsigned CMiniDexedHDMI::GetChunk(u32 *pBuffer, unsigned nChunkSize)
+{
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Start ();
+	}
+
+	unsigned nResult = nChunkSize;
+
+	int16_t SampleBuffer[nChunkSize/2];
+	getSamples (nChunkSize/2, SampleBuffer);
+
+	unsigned nFrame = 0;
+	for (unsigned i = 0; nChunkSize > 0; nChunkSize -= 2)		// fill the whole buffer
+	{
+		s32 nSample = SampleBuffer[i++];
+		nSample <<= 8;
+
+		nSample = ConvertIEC958Sample (nSample, nFrame);
+		if (++nFrame == IEC958_FRAMES_PER_BLOCK)
 		{
-			m_GetChunkTimer.Stop ();
+			nFrame = 0;
 		}
+
+		*pBuffer++ = nSample;		// 2 stereo channels
+		*pBuffer++ = nSample;
 	}
-}
+
+	if (m_bProfileEnabled)
+	{
+		m_GetChunkTimer.Stop();
+	}
+
+	return nResult;
+};
diff --git a/src/minidexed.h b/src/minidexed.h
index ae0eff6..d817f87 100644
--- a/src/minidexed.h
+++ b/src/minidexed.h
@@ -33,34 +33,25 @@
 #include <circle/interrupt.h>
 #include <circle/gpiomanager.h>
 #include <circle/i2cmaster.h>
-#include <circle/multicore.h>
-#include <circle/soundbasedevice.h>
+#include <circle/pwmsoundbasedevice.h>
+#include <circle/i2ssoundbasedevice.h>
+#include <circle/hdmisoundbasedevice.h>
 
 class CMiniDexed : public CDexedAdapter
-#ifdef ARM_ALLOW_MULTI_CORE
-	, public CMultiCoreSupport
-#endif
 {
 public:
 	CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
-		    CGPIOManager *pGPIOManager, CI2CMaster *pI2CMaster);
+		    CGPIOManager *pGPIOManager);
 
-	bool Initialize (void);
+	virtual bool Initialize (void);
 
 	void Process (bool bPlugAndPlayUpdated);
 
-#ifdef ARM_ALLOW_MULTI_CORE
-	void Run (unsigned nCore);
-#endif
-
 	CSysExFileLoader *GetSysExFileLoader (void);
 
 	void BankSelectLSB (unsigned nBankLSB);
 	void ProgramChange (unsigned nProgram);
 
-private:
-	void ProcessSound (void);
-
 private:
 	CConfig *m_pConfig;
 
@@ -72,12 +63,48 @@ private:
 	CSerialMIDIDevice m_SerialMIDI;
 	bool m_bUseSerial;
 
-	CSoundBaseDevice *m_pSoundDevice;
-	unsigned m_nQueueSizeFrames;
-
 protected:
 	CPerformanceTimer m_GetChunkTimer;
 	bool m_bProfileEnabled;
 };
 
+//// PWM //////////////////////////////////////////////////////////////////////
+
+class CMiniDexedPWM : public CMiniDexed, public CPWMSoundBaseDevice
+{
+public:
+	CMiniDexedPWM (CConfig *pConfig, CInterruptSystem *pInterrupt,
+		       CGPIOManager *pGPIOManager);
+
+	bool Initialize (void);
+
+	unsigned GetChunk (u32 *pBuffer, unsigned nChunkSize);
+};
+
+//// I2S //////////////////////////////////////////////////////////////////////
+
+class CMiniDexedI2S : public CMiniDexed, public CI2SSoundBaseDevice
+{
+public:
+	CMiniDexedI2S (CConfig *pConfig, CInterruptSystem *pInterrupt,
+		       CGPIOManager *pGPIOManager, CI2CMaster *pI2CMaster);
+
+	bool Initialize (void);
+
+	unsigned GetChunk (u32 *pBuffer, unsigned nChunkSize);
+};
+
+//// HDMI /////////////////////////////////////////////////////////////////////
+
+class CMiniDexedHDMI : public CMiniDexed, public CHDMISoundBaseDevice
+{
+public:
+	CMiniDexedHDMI (CConfig *pConfig, CInterruptSystem *pInterrupt,
+			CGPIOManager *pGPIOManager);
+
+	bool Initialize (void);
+
+	unsigned GetChunk (u32 *pBuffer, unsigned nChunkSize);
+};
+
 #endif