diff --git a/src/engine/dispatchContainer.cpp b/src/engine/dispatchContainer.cpp
index 4a5fafab5..0da8735d2 100644
--- a/src/engine/dispatchContainer.cpp
+++ b/src/engine/dispatchContainer.cpp
@@ -328,6 +328,7 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
       ((DivPlatformNES*)dispatch)->set5E01(false);
       break;
     case DIV_SYSTEM_C64_6581:
+    case DIV_SYSTEM_C64_PCM:
       dispatch=new DivPlatformC64;
       if (isRender) {
         ((DivPlatformC64*)dispatch)->setCore(eng->getConfInt("c64CoreRender",1));
diff --git a/src/engine/instrument.cpp b/src/engine/instrument.cpp
index f068015cd..4da6cbaef 100644
--- a/src/engine/instrument.cpp
+++ b/src/engine/instrument.cpp
@@ -37,6 +37,7 @@ bool DivInstrumentFM::operator==(const DivInstrumentFM& other) {
     _C(ams2) &&
     _C(ops) &&
     _C(opllPreset) &&
+    _C(block) &&
     _C(fixedDrums) &&
     _C(kickFreq) &&
     _C(snareHatFreq) &&
diff --git a/src/engine/platform/c64.cpp b/src/engine/platform/c64.cpp
index 92f9d1b99..346af821a 100644
--- a/src/engine/platform/c64.cpp
+++ b/src/engine/platform/c64.cpp
@@ -100,9 +100,50 @@ short DivPlatformC64::runFakeFilter(unsigned char ch, int in) {
   return CLAMP(fout,-32768,32767);
 }
 
+void DivPlatformC64::processDAC(int sRate) {
+  bool didWrite=false;
+  if (chan[3].sample>=0 && chan[3].sample<parent->song.sampleLen) {
+    chan[3].pcmPeriod-=chan[3].pcmRate*4;
+    while (chan[3].pcmPeriod<0) {
+      chan[3].pcmPeriod+=sRate;
+      DivSample* s=parent->getSample(chan[3].sample);
+      if (s!=NULL) {
+        if (chan[3].pcmPos<0 || chan[3].pcmPos>=(int)s->samples) {
+          chan[3].pcmOut=15;
+          didWrite=true;
+        } else {
+          chan[3].pcmOut=(0x80+s->data8[chan[3].pcmPos])>>4;
+          didWrite=true;
+        }
+        chan[3].pcmPos++;
+
+        if (s->isLoopable() && chan[3].pcmPos>=s->loopEnd) {
+          chan[3].pcmPos=s->loopStart;
+        } else if (chan[3].pcmPos>=(int)s->samples) {
+          chan[3].sample=-1;
+          didWrite=true;
+        }
+      } else {
+        chan[3].sample=-1;
+        didWrite=true;
+      }
+    }
+  }
+
+  if (didWrite && !isMuted[3]) updateVolume();
+}
+
 void DivPlatformC64::acquire(short** buf, size_t len) {
   int dcOff=(sidCore)?0:sid->get_dc(0);
   for (size_t i=0; i<len; i++) {
+    // run PCM
+    pcmCycle+=lineRate;
+    while (pcmCycle>=(rate*2)) {
+      pcmCycle-=(rate*2);
+      processDAC(lineRate);
+    }
+
+    // the rest
     if (!writes.empty()) {
       QueuedWrite w=writes.front();
       if (sidCore==2) {
@@ -149,7 +190,15 @@ void DivPlatformC64::updateFilter() {
   rWrite(0x15,filtCut&7);
   rWrite(0x16,filtCut>>3);
   rWrite(0x17,(filtRes<<4)|(chan[2].filter<<2)|(chan[1].filter<<1)|(int)(chan[0].filter));
-  rWrite(0x18,(filtControl<<4)|vol);
+  updateVolume();
+}
+
+void DivPlatformC64::updateVolume() {
+  if (chan[3].sample>=0 && !isMuted[3]) {
+    rWrite(0x18,(filtControl<<4)|chan[3].pcmOut);
+  } else {
+    rWrite(0x18,(filtControl<<4)|vol);
+  }
 }
 
 void DivPlatformC64::tick(bool sysTick) {
@@ -308,14 +357,64 @@ void DivPlatformC64::tick(bool sysTick) {
       chan[i].freqChanged=false;
     }
   }
+
+  if (chan[3].freqChanged) {
+    int i=3;
+    double off=1.0;
+    if (chan[i].sample>=0 && chan[i].sample<parent->song.sampleLen) {
+      DivSample* s=parent->getSample(chan[i].sample);
+      if (s->centerRate<1) {
+        off=1.0;
+      } else {
+        off=(double)s->centerRate/8363.0;
+      }
+    }
+    chan[i].pcmRate=off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,2,1);
+    if (dumpWrites) addWrite(0xffff0001+(i<<8),chan[i].pcmRate);
+  }
+
   if (willUpdateFilter) updateFilter();
 }
 
 int DivPlatformC64::dispatch(DivCommand c) {
-  if (c.chan>2) return 0;
+  if (c.chan>3) return 0;
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins,DIV_INS_C64);
+
+      if (chan[c.chan].pcm || c.chan>2) {
+        if (skipRegisterWrites) break;
+        if (c.value!=DIV_NOTE_NULL) {
+          chan[c.chan].sample=ins->amiga.getSample(c.value);
+          chan[c.chan].sampleNote=c.value;
+          c.value=ins->amiga.getFreq(c.value);
+          chan[c.chan].sampleNoteDelta=c.value-chan[c.chan].sampleNote;
+        } else if (chan[c.chan].sampleNote!=DIV_NOTE_NULL) {
+          chan[c.chan].sample=ins->amiga.getSample(chan[c.chan].sampleNote);
+          c.value=ins->amiga.getFreq(chan[c.chan].sampleNote);
+        }
+        if (chan[c.chan].sample<0 || chan[c.chan].sample>=parent->song.sampleLen) {
+          chan[c.chan].sample=-1;
+          if (dumpWrites) addWrite(0xffff0002+(c.chan<<8),0);
+          break;
+        }
+        if (chan[c.chan].setPos) {
+          chan[c.chan].setPos=false;
+        } else {
+          chan[c.chan].pcmPos=0;
+        }
+        chan[c.chan].pcmPeriod=0;
+        if (c.value!=DIV_NOTE_NULL) {
+          chan[c.chan].baseFreq=parent->calcBaseFreq(2,1,c.value,false);
+          chan[c.chan].freqChanged=true;
+          chan[c.chan].note=c.value;
+        }
+        chan[c.chan].active=true;
+        chan[c.chan].macroInit(ins);
+        chan[c.chan].keyOn=true;
+        break;
+      }
+
       if (c.value!=DIV_NOTE_NULL) {
         chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
         chan[c.chan].freqChanged=true;
@@ -364,18 +463,22 @@ int DivPlatformC64::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_OFF:
+      chan[c.chan].sample=-1;
+      chan[c.chan].pcm=false;
       chan[c.chan].active=false;
       chan[c.chan].keyOff=true;
       chan[c.chan].keyOn=false;
       //chan[c.chan].macroInit(NULL);
       break;
     case DIV_CMD_NOTE_OFF_ENV:
+      if (c.chan>2) break;
       chan[c.chan].active=false;
       chan[c.chan].keyOff=true;
       chan[c.chan].keyOn=false;
       chan[c.chan].std.release();
       break;
     case DIV_CMD_ENV_RELEASE:
+      if (c.chan>2) break;
       chan[c.chan].std.release();
       break;
     case DIV_CMD_INSTRUMENT:
@@ -385,6 +488,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_VOLUME:
+      if (c.chan>2) break;
       if (chan[c.chan].vol!=c.value) {
         chan[c.chan].vol=c.value;
         if (!chan[c.chan].std.vol.has) {
@@ -405,6 +509,9 @@ int DivPlatformC64::dispatch(DivCommand c) {
       break;
     case DIV_CMD_NOTE_PORTA: {
       int destFreq=NOTE_FREQUENCY(c.value2);
+      if (c.chan>2 || chan[c.chan].pcm) {
+        destFreq=parent->calcBaseFreq(2,1,c.value2+chan[c.chan].sampleNoteDelta,false);
+      }
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -427,21 +534,28 @@ int DivPlatformC64::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_STD_NOISE_MODE:
+      if (c.chan>2) break;
       chan[c.chan].duty=(c.value*4095)/100;
       rWrite(c.chan*7+2,chan[c.chan].duty&0xff);
       rWrite(c.chan*7+3,chan[c.chan].duty>>8);
       break;
     case DIV_CMD_C64_FINE_DUTY:
+      if (c.chan>2) break;
       chan[c.chan].duty=c.value;
       rWrite(c.chan*7+2,chan[c.chan].duty&0xff);
       rWrite(c.chan*7+3,chan[c.chan].duty>>8);
       break;
     case DIV_CMD_WAVE:
+      if (c.chan>2) break;
       chan[c.chan].wave=c.value;
       rWrite(c.chan*7+4,(chan[c.chan].wave<<4)|(chan[c.chan].test<<3)|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active && chan[c.chan].gate));
       break;
     case DIV_CMD_LEGATO:
-      chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value+((HACKY_LEGATO_MESS)?(chan[c.chan].std.arp.val):(0)));
+      if (c.chan>2 || chan[c.chan].pcm) {
+        chan[c.chan].baseFreq=parent->calcBaseFreq(2,1,c.value+chan[c.chan].sampleNoteDelta+((HACKY_LEGATO_MESS)?(chan[c.chan].std.arp.val):(0)),false);
+      } else {
+        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value+((HACKY_LEGATO_MESS)?(chan[c.chan].std.arp.val):(0)));
+      }
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -456,36 +570,44 @@ int DivPlatformC64::dispatch(DivCommand c) {
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
+      if (c.chan>2) break;
       if (resetTime) chan[c.chan].testWhen=c.value-resetTime+1;
       break;
     case DIV_CMD_GET_VOLMAX:
       return 15;
       break;
     case DIV_CMD_C64_CUTOFF:
+      if (c.chan>2) break;
       if (c.value>100) c.value=100;
       filtCut=(c.value+2)*2047/102;
       updateFilter();
       break;
     case DIV_CMD_C64_FINE_CUTOFF:
+      if (c.chan>2) break;
       filtCut=c.value;
       updateFilter();
       break;
     case DIV_CMD_C64_RESONANCE:
+      if (c.chan>2) break;
       if (c.value>15) c.value=15;
       filtRes=c.value;
       updateFilter();
       break;
     case DIV_CMD_C64_FILTER_MODE:
+      if (c.chan>2) break;
       filtControl=c.value&7;
       updateFilter();
       break;
     case DIV_CMD_C64_RESET_TIME:
+      if (c.chan>2) break;
       resetTime=c.value;
       break;
     case DIV_CMD_C64_RESET_MASK:
+      if (c.chan>2) break;
       chan[c.chan].resetMask=c.value;
       break;
     case DIV_CMD_C64_FILTER_RESET:
+      if (c.chan>2) break;
       if (c.value&15) {
         DivInstrument* ins=parent->getIns(chan[c.chan].ins,DIV_INS_C64);
         if (ins->c64.initFilter) {
@@ -496,6 +618,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       chan[c.chan].resetFilter=c.value>>4;
       break;
     case DIV_CMD_C64_DUTY_RESET:
+      if (c.chan>2) break;
       if (c.value&15) {
         DivInstrument* ins=parent->getIns(chan[c.chan].ins,DIV_INS_C64);
         chan[c.chan].duty=ins->c64.duty;
@@ -505,6 +628,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       chan[c.chan].resetDuty=c.value>>4;
       break;
     case DIV_CMD_C64_EXTENDED:
+      if (c.chan>2) break;
       switch (c.value>>4) {
         case 0:
           chan[c.chan].attack=c.value&15;
@@ -545,19 +669,23 @@ int DivPlatformC64::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_C64_AD:
+      if (c.chan>2) break;
       chan[c.chan].attack=c.value>>4;
       chan[c.chan].decay=c.value&15;
       rWrite(c.chan*7+5,(chan[c.chan].attack<<4)|(chan[c.chan].decay));
       break;
     case DIV_CMD_C64_SR:
+      if (c.chan>2) break;
       chan[c.chan].sustain=c.value>>4;
       chan[c.chan].release=c.value&15;
       rWrite(c.chan*7+6,(chan[c.chan].sustain<<4)|(chan[c.chan].release));
       break;
     case DIV_CMD_C64_PW_SLIDE:
+      if (c.chan>2) break;
       chan[c.chan].pw_slide=c.value*c.value2;
       break;
     case DIV_CMD_C64_CUTOFF_SLIDE:
+      if (c.chan>2) break;
       cutoff_slide=c.value*c.value2;
       break;
     case DIV_CMD_MACRO_OFF:
@@ -589,10 +717,11 @@ void DivPlatformC64::muteChannel(int ch, bool mute) {
   } else {
     sid->set_is_muted(ch,mute);
   }
+  if (ch==3) updateVolume();
 }
 
 void DivPlatformC64::forceIns() {
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     chan[i].insChanged=true;
     chan[i].testWhen=0;
     if (chan[i].active) {
@@ -604,7 +733,7 @@ void DivPlatformC64::forceIns() {
 }
 
 void DivPlatformC64::notifyInsChange(int ins) {
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     if (chan[i].ins==ins) {
       chan[i].insChanged=true;
     }
@@ -612,7 +741,7 @@ void DivPlatformC64::notifyInsChange(int ins) {
 }
 
 void DivPlatformC64::notifyInsDeletion(void* ins) {
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     chan[i].std.notifyInsDeletion((DivInstrument*)ins);
   }
 }
@@ -690,7 +819,7 @@ float DivPlatformC64::getPostAmp() {
 
 void DivPlatformC64::reset() {
   while (!writes.empty()) writes.pop();
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     chan[i]=DivPlatformC64::Channel();
     chan[i].std.setEngine(parent);
     fakeLow[i]=0;
@@ -699,6 +828,7 @@ void DivPlatformC64::reset() {
   }
 
   cutoff_slide=0;
+  pcmCycle=0;
 
   if (sidCore==2) {
     dSID_init(sid_d,chipClock,rate,sidIs6581?6581:8580,needInitTables);
@@ -761,18 +891,21 @@ void DivPlatformC64::setFlags(const DivConfig& flags) {
   switch (flags.getInt("clockSel",0)) {
     case 0x0: // NTSC C64
       chipClock=COLOR_NTSC*2.0/7.0;
+      lineRate=15734;
       break;
     case 0x1: // PAL C64
       chipClock=COLOR_PAL*2.0/9.0;
+      lineRate=15625;
       break;
     case 0x2: // SSI 2001
     default:
       chipClock=14318180.0/16.0;
+      lineRate=15734;
       break;
   }
   CHECK_CUSTOM_CLOCK;
   rate=chipClock;
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     oscBuf[i]->rate=rate/16;
   }
   if (sidCore>0) {
@@ -839,7 +972,7 @@ int DivPlatformC64::init(DivEngine* p, int channels, int sugRate, const DivConfi
   skipRegisterWrites=false;
   needInitTables=true;
   writeOscBuf=0;
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     isMuted[i]=false;
     oscBuf[i]=new DivDispatchOscBuffer;
   }
@@ -884,7 +1017,7 @@ int DivPlatformC64::init(DivEngine* p, int channels, int sugRate, const DivConfi
 }
 
 void DivPlatformC64::quit() {
-  for (int i=0; i<3; i++) {
+  for (int i=0; i<4; i++) {
     delete oscBuf[i];
   }
   if (sid!=NULL) delete sid;
diff --git a/src/engine/platform/c64.h b/src/engine/platform/c64.h
index f2290c805..9bb449145 100644
--- a/src/engine/platform/c64.h
+++ b/src/engine/platform/c64.h
@@ -33,8 +33,8 @@
 class DivPlatformC64: public DivDispatch {
   struct Channel: public SharedChannel<signed char> {
     int prevFreq, testWhen;
-    unsigned int audPos, pcmPos;
-    int sample, pcmPeriod, pcmRate, pcmOut;
+    unsigned int audPos;
+    int pcmPos, sample, pcmPeriod, pcmRate, pcmOut;
     unsigned char sweep, wave, attack, decay, sustain, release;
     short duty;
     bool sweepChanged, filter, setPos, pcm;
@@ -49,7 +49,7 @@ class DivPlatformC64: public DivDispatch {
       sample(-1),
       pcmPeriod(0),
       pcmRate(0),
-      pcmOut(0),
+      pcmOut(15),
       sweep(0),
       wave(0),
       attack(0),
@@ -88,6 +88,7 @@ class DivPlatformC64: public DivDispatch {
   unsigned char writeOscBuf;
   unsigned char sidCore;
   int filtCut, resetTime, initResetTime;
+  int pcmCycle, lineRate;
   short cutoff_slide;
 
   bool keyPriority, sidIs6581, needInitTables, no1EUpdate, multiplyRel, macroRace;
@@ -105,10 +106,12 @@ class DivPlatformC64: public DivDispatch {
 
   inline short runFakeFilter(unsigned char ch, int in);
 
+  void processDAC(int sRate);
   void acquire_classic(short* bufL, short* bufR, size_t start, size_t len);
   void acquire_fp(short* bufL, short* bufR, size_t start, size_t len);
 
   void updateFilter();
+  void updateVolume();
   public:
     void acquire(short** buf, size_t len);
     int dispatch(DivCommand c);
diff --git a/src/engine/song.h b/src/engine/song.h
index a6da6b3d4..e2f8f95be 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -145,6 +145,7 @@ enum DivSystem {
   DIV_SYSTEM_SUPERVISION,
   DIV_SYSTEM_UPD1771C,
   DIV_SYSTEM_SID3,
+  DIV_SYSTEM_C64_PCM,
 
   DIV_SYSTEM_MAX
 };
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index 3753986ce..160b24fd2 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -2316,6 +2316,18 @@ void DivEngine::registerSystems() {
     SID3PostEffectHandlerMap
   );
 
+  sysDefs[DIV_SYSTEM_C64_PCM]=new DivSysDef(
+    _("Commodore 64 (SID 6581) with software PCM"), NULL, 0xe2, 0, 4, false, true, 0, false, (1U<<DIV_SAMPLE_DEPTH_8BIT)|(1U<<DIV_SAMPLE_DEPTH_16BIT), 0, 0,
+    _("the 6581 had a quirk which allowed playback of 4-bit samples by writing PCM data to the volume register."),
+    {_("Channel 1"), _("Channel 2"), _("Channel 3"), _("PCM")},
+    {"CH1", "CH2", "CH3", "P"},
+    {DIV_CH_NOISE, DIV_CH_NOISE, DIV_CH_NOISE, DIV_CH_PCM},
+    {DIV_INS_C64, DIV_INS_C64, DIV_INS_C64, DIV_INS_AMIGA},
+    {},
+    {},
+    c64PostEffectHandlerMap
+  );
+
   sysDefs[DIV_SYSTEM_DUMMY]=new DivSysDef(
     _("Dummy System"), NULL, 0xfd, 0, 8, false, true, 0, false, 0, 0, 0,
     _("this is a system designed for testing purposes."),
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index 06147c3fa..aea4901cb 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -1228,6 +1228,7 @@ const int availableSystems[]={
   DIV_SYSTEM_NES,
   DIV_SYSTEM_C64_8580,
   DIV_SYSTEM_C64_6581,
+  DIV_SYSTEM_C64_PCM,
   DIV_SYSTEM_YM2151,
   DIV_SYSTEM_SEGAPCM,
   DIV_SYSTEM_SEGAPCM_COMPAT,
@@ -1402,6 +1403,7 @@ const int chipsSpecial[]={
   DIV_SYSTEM_NES,
   DIV_SYSTEM_C64_8580,
   DIV_SYSTEM_C64_6581,
+  DIV_SYSTEM_C64_PCM,
   DIV_SYSTEM_SFX_BEEPER,
   DIV_SYSTEM_SFX_BEEPER_QUADTONE,
   DIV_SYSTEM_DUMMY,
diff --git a/src/gui/sysConf.cpp b/src/gui/sysConf.cpp
index 4f57e328f..4116909c5 100644
--- a/src/gui/sysConf.cpp
+++ b/src/gui/sysConf.cpp
@@ -680,7 +680,8 @@ bool FurnaceGUI::drawSysConf(int chan, int sysPos, DivSystem type, DivConfig& fl
       break;
     }
     case DIV_SYSTEM_C64_8580:
-    case DIV_SYSTEM_C64_6581: {
+    case DIV_SYSTEM_C64_6581:
+    case DIV_SYSTEM_C64_PCM: {
       int clockSel=flags.getInt("clockSel",0);
       bool keyPriority=flags.getBool("keyPriority",true);
       bool no1EUpdate=flags.getBool("no1EUpdate",false);