diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 38149e462..d70f03053 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -691,7 +691,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
           ins->c64.s=reader.readC();
           ins->c64.r=reader.readC();
 
-          ins->c64.duty=reader.readC();
+          ins->c64.duty=(reader.readC()*4095)/100;
 
           ins->c64.ringMod=reader.readC();
           ins->c64.oscSync=reader.readC();
@@ -704,7 +704,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
           ins->c64.initFilter=reader.readC();
 
           ins->c64.res=reader.readC();
-          ins->c64.cut=reader.readC();
+          ins->c64.cut=(reader.readC()*2047)/100;
           ins->c64.hp=reader.readC();
           ins->c64.bp=reader.readC();
           ins->c64.lp=reader.readC();
@@ -1534,7 +1534,7 @@ SafeWriter* DivEngine::saveFur() {
     w->writeC(ins->c64.d);
     w->writeC(ins->c64.s);
     w->writeC(ins->c64.r);
-    w->writeS((ins->c64.duty*4096)/100);
+    w->writeS(ins->c64.duty);
     w->writeC(ins->c64.ringMod);
     w->writeC(ins->c64.oscSync);
     w->writeC(ins->c64.toFilter);
@@ -1545,7 +1545,7 @@ SafeWriter* DivEngine::saveFur() {
     w->writeC(ins->c64.bp);
     w->writeC(ins->c64.hp);
     w->writeC(ins->c64.ch3off);
-    w->writeS((ins->c64.cut*2047)/100);
+    w->writeS(ins->c64.cut);
     w->writeC(ins->c64.dutyIsAbs);
     w->writeC(ins->c64.filterIsAbs);
     
@@ -1783,7 +1783,8 @@ SafeWriter* DivEngine::saveDMF() {
         w->writeC(i->c64.s);
         w->writeC(i->c64.r);
 
-        w->writeC(i->c64.duty);
+        logW("duty and cutoff precision will be lost!\n");
+        w->writeC((i->c64.duty*100)/4095);
 
         w->writeC(i->c64.ringMod);
         w->writeC(i->c64.oscSync);
@@ -1793,7 +1794,7 @@ SafeWriter* DivEngine::saveDMF() {
         w->writeC(i->c64.initFilter);
 
         w->writeC(i->c64.res);
-        w->writeC(i->c64.cut);
+        w->writeC((i->c64.cut*100)/2047);
         w->writeC(i->c64.hp);
         w->writeC(i->c64.bp);
         w->writeC(i->c64.lp);
diff --git a/src/engine/instrument.h b/src/engine/instrument.h
index 70b9b1ec2..36ff978c1 100644
--- a/src/engine/instrument.h
+++ b/src/engine/instrument.h
@@ -116,10 +116,11 @@ struct DivInstrumentGB {
 struct DivInstrumentC64 {
   bool triOn, sawOn, pulseOn, noiseOn;
   unsigned char a, d, s, r;
-  unsigned char duty;
+  unsigned short duty;
   unsigned char ringMod, oscSync;
   bool toFilter, volIsCutoff, initFilter, dutyIsAbs, filterIsAbs;
-  unsigned char res, cut;
+  unsigned char res;
+  unsigned short cut;
   bool hp, lp, bp, ch3off;
 
   DivInstrumentC64():
@@ -131,7 +132,7 @@ struct DivInstrumentC64 {
     d(8),
     s(0),
     r(0),
-    duty(50),
+    duty(2048),
     ringMod(0),
     oscSync(0),
     toFilter(false),
diff --git a/src/engine/platform/c64.cpp b/src/engine/platform/c64.cpp
index 6f376ecd5..e26aca80a 100644
--- a/src/engine/platform/c64.cpp
+++ b/src/engine/platform/c64.cpp
@@ -100,7 +100,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       chan[c.chan].active=true;
       chan[c.chan].keyOn=true;
       if (chan[c.chan].insChanged || chan[c.chan].resetDuty || ins->std.waveMacroLen>0) {
-        chan[c.chan].duty=(ins->c64.duty*4095)/100;
+        chan[c.chan].duty=ins->c64.duty;
         rWrite(c.chan*7+2,chan[c.chan].duty&0xff);
         rWrite(c.chan*7+3,chan[c.chan].duty>>8);
       }
@@ -116,7 +116,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       if (chan[c.chan].insChanged || chan[c.chan].resetFilter) {
         chan[c.chan].filter=ins->c64.toFilter;
         if (ins->c64.initFilter) {
-          filtCut=ins->c64.cut*2047/100;
+          filtCut=ins->c64.cut;
           filtRes=ins->c64.res;
           filtControl=ins->c64.lp|(ins->c64.bp<<1)|(ins->c64.hp<<2)|(ins->c64.ch3off<<3);
           updateFilter();
@@ -229,7 +229,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
     case DIV_CMD_C64_FILTER_RESET:
       if (c.value&15) {
         DivInstrument* ins=parent->getIns(chan[c.chan].ins);
-        filtCut=ins->c64.cut*2047/100;
+        filtCut=ins->c64.cut;
         updateFilter();
       }
       chan[c.chan].resetFilter=c.value>>4;
@@ -237,7 +237,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
     case DIV_CMD_C64_DUTY_RESET:
       if (c.value&15) {
         DivInstrument* ins=parent->getIns(chan[c.chan].ins);
-        chan[c.chan].duty=(ins->c64.duty*4095)/100;
+        chan[c.chan].duty=ins->c64.duty;
         rWrite(c.chan*7+2,chan[c.chan].duty&0xff);
         rWrite(c.chan*7+3,chan[c.chan].duty>>8);
       }
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 3bfa3d971..cb96b6522 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -38,6 +38,8 @@ const int _THIRTY_ONE=31;
 const int _SIXTY_FOUR=64;
 const int _ONE_HUNDRED=100;
 const int _ONE_HUNDRED_TWENTY_SEVEN=127;
+const int _TWO_THOUSAND_FORTY_SEVEN=2047;
+const int _FOUR_THOUSAND_NINETY_FIVE=4095;
 
 const FurnaceGUIColors fxColors[16]={
   GUI_COLOR_PATTERN_EFFECT_MISC, // 00
@@ -666,7 +668,7 @@ void FurnaceGUI::drawInsEdit() {
           ImGui::SliderScalar("Decay",ImGuiDataType_U8,&ins->c64.d,&_ZERO,&_FIFTEEN);
           ImGui::SliderScalar("Sustain",ImGuiDataType_U8,&ins->c64.s,&_ZERO,&_FIFTEEN);
           ImGui::SliderScalar("Release",ImGuiDataType_U8,&ins->c64.r,&_ZERO,&_FIFTEEN);
-          ImGui::SliderScalar("Duty",ImGuiDataType_U8,&ins->c64.duty,&_ZERO,&_ONE_HUNDRED);
+          ImGui::SliderScalar("Duty",ImGuiDataType_U16,&ins->c64.duty,&_ZERO,&_FOUR_THOUSAND_NINETY_FIVE);
 
           bool ringMod=ins->c64.ringMod;
           if (ImGui::Checkbox("Ring Modulation",&ringMod)) ins->c64.ringMod=ringMod;
@@ -676,7 +678,7 @@ void FurnaceGUI::drawInsEdit() {
           ImGui::Checkbox("Enable filter",&ins->c64.toFilter);
           ImGui::Checkbox("Initialize filter",&ins->c64.initFilter);
           
-          ImGui::SliderScalar("Cutoff",ImGuiDataType_U8,&ins->c64.cut,&_ZERO,&_ONE_HUNDRED);
+          ImGui::SliderScalar("Cutoff",ImGuiDataType_U16,&ins->c64.cut,&_ZERO,&_TWO_THOUSAND_FORTY_SEVEN);
           ImGui::SliderScalar("Resonance",ImGuiDataType_U8,&ins->c64.res,&_ZERO,&_FIFTEEN);
 
           ImGui::Text("Filter Mode");