diff --git a/src/Makefile b/src/Makefile
index c8b7971..736b7c2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -41,7 +41,7 @@ endif
 
 ifeq ($(DEBUG), 1)
    ifeq ($(FILETRACE), 1)
-      CXXFLAGS += -DDEBUG -DFILETRACE $(CFLAGS) -D PATCH_DEBUG
+      CXXFLAGS += -DDEBUG -DFILETRACE $(CFLAGS)
    else
       CXXFLAGS += -DDEBUG $(CFLAGS)
    endif
diff --git a/src/dexed.cpp b/src/dexed.cpp
index 4e92ef5..7a0a291 100644
--- a/src/dexed.cpp
+++ b/src/dexed.cpp
@@ -104,6 +104,10 @@ void Dexed::activate(void)
 
   set_params();
 
+#ifdef DEBUG
+  TRACE("Algorithm %d outputs: %d",data[134],controllers.core->op_out(data[134]));
+#endif
+
   Plugin::activate();
 
   TRACE("Bye");
@@ -447,18 +451,25 @@ void Dexed::GetSamples(uint32_t n_samples, float* buffer)
     if(voices[i].live==true && voices[i].keydown==false)
     {
       uint8_t op_amp=0;
+      uint8_t op_out=controllers.core->op_out(data[134]);
+      uint8_t op_carrier_num=0;
 
       voices[i].dx7_note->peekVoiceStatus(voiceStatus);
 
       for(uint8_t op=0;op<6;op++)
       {
-//        TRACE("Voice[%2d] OP [%d] amp=%ld,amp_step=%d,pitch_step=%d",i,op,voiceStatus.amp[op],voiceStatus.ampStep[op],voiceStatus.pitchStep);
-
-        if(voiceStatus.amp[op]<=1069)
-          op_amp++;
-
+        if((op_out&op)==1)
+        {
+          // this voice is a carrier!
+          op_carrier_num++;
+
+          TRACE("Voice[%2d] OP [%d] amp=%ld,amp_step=%d,pitch_step=%d",i,op,voiceStatus.amp[op],voiceStatus.ampStep[op],voiceStatus.pitchStep);
+       
+          if(voiceStatus.amp[op]<=1069)
+            op_amp++;
+        }
       }
-      if(op_amp==6)
+      if(op_amp==op_carrier_num)
         voices[i].live=false;
     }
 //    TRACE("Voice[%2d] live=%d keydown=%d",i,voices[i].live,voices[i].keydown);
diff --git a/src/msfa/fm_core.cc b/src/msfa/fm_core.cc
index a408c55..6001175 100644
--- a/src/msfa/fm_core.cc
+++ b/src/msfa/fm_core.cc
@@ -68,6 +68,22 @@ int n_out(const FmAlgorithm &alg) {
   return count;
 }
 
+uint8_t FmCore::op_out(uint8_t algorithm)
+{
+  uint8_t op_out=0;
+  FmAlgorithm alg=algorithms[algorithm];
+
+  for(uint8_t i=0; i<6;i++)
+  {
+    if((alg.ops[i]&OUT_BUS_ADD)==OUT_BUS_ADD)
+      op_out|=1<<i;
+    TRACE("OP[%d]:",6-i);
+    TRACE("OUT_BUS_ONE=%d OUT_BUS_TWO=%d OUT_BUS_ADD=%d IN_BUS_ONE=%d IN_BUS_TWO=%d FB_IN=%d FB_OUT=%d",alg.ops[i]&OUT_BUS_ONE?1:0,alg.ops[i]&OUT_BUS_TWO?1:0,alg.ops[i]&OUT_BUS_ADD?1:0,alg.ops[i]&IN_BUS_ONE?1:0,alg.ops[i]&IN_BUS_TWO?1:0,alg.ops[i]&FB_IN?1:0,alg.ops[i]&FB_OUT?1:0);
+  }
+
+  return op_out;
+}
+
 void FmCore::dump() {
 #ifdef VERBOSE
   for (int i = 0; i < 32; i++) {
diff --git a/src/msfa/fm_core.h b/src/msfa/fm_core.h
index 003f3ca..af134cb 100644
--- a/src/msfa/fm_core.h
+++ b/src/msfa/fm_core.h
@@ -48,6 +48,7 @@ class FmCore {
 public:
     virtual ~FmCore() {};
     static void dump();
+    uint8_t op_out(uint8_t algorithm);
     virtual void render(int32_t *output, FmOpParams *params, int algorithm, int32_t *fb_buf, int32_t feedback_gain);
 protected:
     AlignedBuf<int32_t, N>buf_[2];