diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index e8bc0f303..e0e44e935 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -93,12 +93,6 @@ bool DivSample::initInternal(unsigned char d, int count) {
       dataDPCM=new unsigned char[lengthDPCM];
       memset(dataDPCM,0,lengthDPCM);
       break;
-    case 2: // AICA ADPCM
-      if (dataAICA!=NULL) delete[] dataAICA;
-      lengthAICA=(count+1)/2;
-      dataAICA=new unsigned char[(lengthAICA+255)&(~0xff)];
-      memset(dataAICA,0,(lengthAICA+255)&(~0xff));
-      break;
     case 3: // YMZ ADPCM
       if (dataZ!=NULL) delete[] dataZ;
       lengthZ=(count+1)/2;
@@ -123,12 +117,6 @@ bool DivSample::initInternal(unsigned char d, int count) {
       dataB=new unsigned char[(lengthB+255)&(~0xff)];
       memset(dataB,0,(lengthB+255)&(~0xff));
       break;
-    case 7: // X68000 ADPCM
-      if (dataX68!=NULL) delete[] dataX68;
-      lengthX68=(count+1)/2;
-      dataX68=new unsigned char[lengthX68];
-      memset(dataX68,0,lengthX68);
-      break;
     case 8: // 8-bit
       if (data8!=NULL) delete[] data8;
       length8=count;
@@ -669,9 +657,6 @@ void DivSample::render() {
         }
         break;
       }
-      case 2: // AICA ADPCM
-        aica_decode(dataAICA,data16,samples);
-        break;
       case 3: // YMZ ADPCM
         ymz_decode(dataZ,data16,samples);
         break;
@@ -684,9 +669,6 @@ void DivSample::render() {
       case 6: // ADPCM-B
         ymb_decode(dataB,data16,samples);
         break;
-      case 7: // X6800 ADPCM
-        oki6258_decode(dataX68,data16,samples);
-        break;
       case 8: // 8-bit PCM
         for (unsigned int i=0; i<samples; i++) {
           data16[i]=data8[i]<<8;
@@ -727,10 +709,6 @@ void DivSample::render() {
       if (accum>127) accum=127;
     }
   }
-  if (depth!=2) { // AICA ADPCM
-    if (!initInternal(2,samples)) return;
-    aica_encode(data16,dataAICA,(samples+511)&(~0x1ff));
-  }
   if (depth!=3) { // YMZ ADPCM
     if (!initInternal(3,samples)) return;
     ymz_encode(data16,dataZ,(samples+511)&(~0x1ff));
@@ -748,10 +726,6 @@ void DivSample::render() {
     if (!initInternal(6,samples)) return;
     ymb_encode(data16,dataB,(samples+511)&(~0x1ff));
   }
-  if (depth!=7) { // X68000 ADPCM
-    if (!initInternal(7,samples)) return;
-    oki6258_encode(data16,dataX68,samples);
-  }
   if (depth!=8) { // 8-bit PCM
     if (!initInternal(8,samples)) return;
     for (unsigned int i=0; i<samples; i++) {
@@ -771,8 +745,6 @@ void* DivSample::getCurBuf() {
       return data1;
     case 1:
       return dataDPCM;
-    case 2:
-      return dataAICA;
     case 3:
       return dataZ;
     case 4:
@@ -781,8 +753,6 @@ void* DivSample::getCurBuf() {
       return dataA;
     case 6:
       return dataB;
-    case 7:
-      return dataX68;
     case 8:
       return data8;
     case 9:
@@ -801,8 +771,6 @@ unsigned int DivSample::getCurBufLen() {
       return length1;
     case 1:
       return lengthDPCM;
-    case 2:
-      return lengthAICA;
     case 3:
       return lengthZ;
     case 4:
@@ -811,8 +779,6 @@ unsigned int DivSample::getCurBufLen() {
       return lengthA;
     case 6:
       return lengthB;
-    case 7:
-      return lengthX68;
     case 8:
       return length8;
     case 9:
@@ -915,12 +881,10 @@ DivSample::~DivSample() {
   if (data16) delete[] data16;
   if (data1) delete[] data1;
   if (dataDPCM) delete[] dataDPCM;
-  if (dataAICA) delete[] dataAICA;
   if (dataZ) delete[] dataZ;
   if (dataQSoundA) delete[] dataQSoundA;
   if (dataA) delete[] dataA;
   if (dataB) delete[] dataB;
-  if (dataX68) delete[] dataX68;
   if (dataBRR) delete[] dataBRR;
   if (dataVOX) delete[] dataVOX;
 }
diff --git a/src/engine/sample.h b/src/engine/sample.h
index 624139797..28c870b57 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -62,15 +62,13 @@ struct DivSample {
   // valid values are:
   // - 0: ZX Spectrum overlay drum (1-bit)
   // - 1: 1-bit NES DPCM (1-bit)
-  // - 2: AICA ADPCM
   // - 3: YMZ ADPCM
   // - 4: QSound ADPCM
   // - 5: ADPCM-A
   // - 6: ADPCM-B
-  // - 7: X68000 ADPCM
   // - 8: 8-bit PCM
   // - 9: BRR (SNES)
-  // - 10: VOX
+  // - 10: VOX ADPCM
   // - 16: 16-bit PCM
   unsigned char depth;
 
@@ -79,17 +77,15 @@ struct DivSample {
   short* data16; // 16
   unsigned char* data1; // 0
   unsigned char* dataDPCM; // 1
-  unsigned char* dataAICA; // 2
   unsigned char* dataZ; // 3
   unsigned char* dataQSoundA; // 4
   unsigned char* dataA; // 5
   unsigned char* dataB; // 6
-  unsigned char* dataX68; // 7
   unsigned char* dataBRR; // 9
   unsigned char* dataVOX; // 10
 
-  unsigned int length8, length16, length1, lengthDPCM, lengthAICA, lengthZ, lengthQSoundA, lengthA, lengthB, lengthX68, lengthBRR, lengthVOX;
-  unsigned int off8, off16, off1, offDPCM, offAICA, offZ, offQSoundA, offA, offB, offX68, offBRR, offVOX;
+  unsigned int length8, length16, length1, lengthDPCM, lengthZ, lengthQSoundA, lengthA, lengthB, lengthBRR, lengthVOX;
+  unsigned int off8, off16, off1, offDPCM, offZ, offQSoundA, offA, offB, offBRR, offVOX;
   unsigned int offSegaPCM, offQSound, offX1_010, offSU;
 
   unsigned int samples;
@@ -222,36 +218,30 @@ struct DivSample {
     data16(NULL),
     data1(NULL),
     dataDPCM(NULL),
-    dataAICA(NULL),
     dataZ(NULL),
     dataQSoundA(NULL),
     dataA(NULL),
     dataB(NULL),
-    dataX68(NULL),
     dataBRR(NULL),
     dataVOX(NULL),
     length8(0),
     length16(0),
     length1(0),
     lengthDPCM(0),
-    lengthAICA(0),
     lengthZ(0),
     lengthQSoundA(0),
     lengthA(0),
     lengthB(0),
-    lengthX68(0),
     lengthBRR(0),
     lengthVOX(0),
     off8(0),
     off16(0),
     off1(0),
     offDPCM(0),
-    offAICA(0),
     offZ(0),
     offQSoundA(0),
     offA(0),
     offB(0),
-    offX68(0),
     offBRR(0),
     offVOX(0),
     offSegaPCM(0),
diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index 9cb642455..07f9a3266 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -162,7 +162,6 @@ void FurnaceGUI::drawDebug() {
           ImGui::Text("lengthQSoundA: %d",sample->lengthQSoundA);
           ImGui::Text("lengthA: %d",sample->lengthA);
           ImGui::Text("lengthB: %d",sample->lengthB);
-          ImGui::Text("lengthX68: %d",sample->lengthX68);
           ImGui::Text("lengthBRR: %d",sample->lengthBRR);
           ImGui::Text("lengthVOX: %d",sample->lengthVOX);
 
@@ -173,7 +172,6 @@ void FurnaceGUI::drawDebug() {
           ImGui::Text("offQSoundA: %x",sample->offQSoundA);
           ImGui::Text("offA: %x",sample->offA);
           ImGui::Text("offB: %x",sample->offB);
-          ImGui::Text("offX68: %x",sample->offX68);
           ImGui::Text("offBRR: %x",sample->offBRR);
           ImGui::Text("offVOX: %x",sample->offVOX);
           ImGui::Text("offSegaPCM: %x",sample->offSegaPCM);
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index 62f065f92..1db6d4139 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -116,12 +116,12 @@ const char* insTypes[DIV_INS_MAX]={
 const char* sampleDepths[17]={
   "1-bit PCM",
   "1-bit DPCM",
-  "Yamaha AICA",
+  NULL,
   "YMZ/YMU ADPCM",
   "QSound ADPCM",
   "ADPCM-A",
   "ADPCM-B",
-  "X68000 ADPCM",
+  NULL,
   "8-bit PCM",
   NULL, // "BRR",
   "VOX",