diff --git a/src/engine/platform/ymz280b.cpp b/src/engine/platform/ymz280b.cpp
index 7d1936524..4f9f6a93a 100644
--- a/src/engine/platform/ymz280b.cpp
+++ b/src/engine/platform/ymz280b.cpp
@@ -136,7 +136,7 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
       DivSample* s=parent->getSample(chan[i].sample);
       unsigned char ctrl;
       switch (s->depth) {
-        case 2: ctrl=0x20; break;
+        case 3: ctrl=0x20; break;
         case 8: ctrl=0x40; break;
         case 16: ctrl=0x60; break;
         default: ctrl=0;
@@ -146,7 +146,7 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
       if (chan[i].freq<0) chan[i].freq=0;
       if (chan[i].freq>511) chan[i].freq=511;
       // ADPCM has half the range
-      if (s->depth==2 && chan[i].freq>255) chan[i].freq=255;
+      if (s->depth==3 && chan[i].freq>255) chan[i].freq=255;
       ctrl|=(chan[i].active?0x80:0)|((s->loopStart>=0)?0x10:0)|(chan[i].freq>>8);
       if (chan[i].keyOn) {
         unsigned int start=s->offYMZ280B;
@@ -154,14 +154,14 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
         unsigned int end=start+s->getCurBufLen();
         if (chan[i].audPos>0) {
           switch (s->depth) {
-            case 2: start+=chan[i].audPos/2; break;
+            case 3: start+=chan[i].audPos/2; break;
             case 8: start+=chan[i].audPos; break;
             case 16: start+=chan[i].audPos*2; break;
           }
         }
         if (s->loopStart>=0) {
           switch (s->depth) {
-            case 2: loop=start+s->loopStart/2; break;
+            case 3: loop=start+s->loopStart/2; break;
             case 8: loop=start+s->loopStart; break;
             case 16: loop=start+s->loopStart*2; break;
           }
diff --git a/src/engine/platform/ymz280b.h b/src/engine/platform/ymz280b.h
index 65d2aa48e..4957d8998 100644
--- a/src/engine/platform/ymz280b.h
+++ b/src/engine/platform/ymz280b.h
@@ -18,7 +18,7 @@
  */
 
 #ifndef _YMZ280B_H
-#define _QSOUND_H
+#define _YMZ280B_H
 
 #include "../dispatch.h"
 #include <queue>
diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index 7847a6621..108b1eb76 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -93,7 +93,7 @@ bool DivSample::initInternal(unsigned char d, int count) {
       dataDPCM=new unsigned char[lengthDPCM];
       memset(dataDPCM,0,lengthDPCM);
       break;
-    case 2: // YMZ ADPCM
+    case 3: // YMZ ADPCM
       if (dataZ!=NULL) delete[] dataZ;
       lengthZ=(count+1)/2;
       // for padding AICA sample
@@ -664,7 +664,7 @@ void DivSample::render() {
         }
         break;
       }
-      case 2: // YMZ ADPCM
+      case 3: // YMZ ADPCM
         ymz_decode(dataZ,data16,samples);
         break;
       case 4: // QSound ADPCM
@@ -719,8 +719,8 @@ void DivSample::render() {
       if (accum>127) accum=127;
     }
   }
-  if (depth!=2) { // YMZ ADPCM
-    if (!initInternal(2,samples)) return;
+  if (depth!=3) { // YMZ ADPCM
+    if (!initInternal(3,samples)) return;
     ymz_encode(data16,dataZ,(samples+7)&(~0x7));
   }
   if (depth!=4) { // QSound ADPCM
@@ -759,7 +759,7 @@ void* DivSample::getCurBuf() {
       return data1;
     case 1:
       return dataDPCM;
-    case 2:
+    case 3:
       return dataZ;
     case 4:
       return dataQSoundA;
@@ -787,7 +787,7 @@ unsigned int DivSample::getCurBufLen() {
       return length1;
     case 1:
       return lengthDPCM;
-    case 2:
+    case 3:
       return lengthZ;
     case 4:
       return lengthQSoundA;
diff --git a/src/engine/sample.h b/src/engine/sample.h
index 67a687c42..2a8385e9c 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -62,7 +62,7 @@ struct DivSample {
   // valid values are:
   // - 0: ZX Spectrum overlay drum (1-bit)
   // - 1: 1-bit NES DPCM (1-bit)
-  // - 2: YMZ ADPCM
+  // - 3: YMZ ADPCM
   // - 4: QSound ADPCM
   // - 5: ADPCM-A
   // - 6: ADPCM-B
@@ -78,7 +78,7 @@ struct DivSample {
   short* data16; // 16
   unsigned char* data1; // 0
   unsigned char* dataDPCM; // 1
-  unsigned char* dataZ; // 2
+  unsigned char* dataZ; // 3
   unsigned char* dataQSoundA; // 4
   unsigned char* dataA; // 5
   unsigned char* dataB; // 6
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index 210f941c5..abafed4e1 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -1885,7 +1885,7 @@ void DivEngine::registerSystems() {
 
   sysDefs[DIV_SYSTEM_YMZ280B]=new DivSysDef(
     "Yamaha YMZ280B", NULL, 0xb8, 0, 8, false, true, 0x151, false,
-    "used in some arcade boards. Has 8 channels of either 4-bit ADPCM, 8-bit PCM or 16-bit PCM.",
+    "used in some arcade boards. Can play back either 4-bit ADPCM, 8-bit PCM or 16-bit PCM.",
     {"PCM 1", "PCM 2", "PCM 3", "PCM 4", "PCM 5", "PCM 6", "PCM 7", "PCM 8"},
     {"1", "2", "3", "4", "5", "6", "7", "8"},
     {DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM},
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index 13cb4986e..44022eded 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -116,8 +116,8 @@ const char* insTypes[DIV_INS_MAX]={
 const char* sampleDepths[17]={
   "1-bit PCM",
   "1-bit DPCM",
-  "YMZ/YMU/AICA ADPCM",
   NULL,
+  "YMZ/YMU/AICA ADPCM",
   "QSound ADPCM",
   "ADPCM-A",
   "ADPCM-B",