diff --git a/software/o_c_REV/APP_DQ.ino b/software/o_c_REV/APP_DQ.ino
index 08deac0d..1371635a 100644
--- a/software/o_c_REV/APP_DQ.ino
+++ b/software/o_c_REV/APP_DQ.ino
@@ -365,7 +365,7 @@ public:
 
     for (int i = 0; i < NUM_SCALE_SLOTS; i++) {
       last_scale_[i] = -1;
-      last_mask_[i] = 0;
+      last_mask_[i] = 0xFFFF;
     }
     
     aux_sample_ = 0;
@@ -434,20 +434,22 @@ public:
       update_asr_ = true;  
       aux_sample_ = ON; 
     }
-         
+
+    if (scale_reset_) {
+      // manual change?
+      scale_reset_ = false;
+      scale_sequence_cnt_ = 0x0;
+      scale_advance_state_ = 0x1;
+      active_scale_slot_ = get_scale_select();
+      prev_scale_slot_ = display_scale_slot_ = active_scale_slot_;
+    }
+    
     if (get_scale_seq_mode()) {
         // to do, don't hardcode .. 
       uint8_t _advance_trig = (dac_channel == DAC_CHANNEL_A) ? digitalReadFast(TR2) : digitalReadFast(TR4);
       if (_advance_trig < scale_advance_state_) 
         scale_advance_ = true;
       scale_advance_state_ = _advance_trig;  
-
-      if (scale_reset_) {
-       // manual change?
-       scale_reset_ = false;
-       active_scale_slot_ = get_scale_select();
-       prev_scale_slot_ = display_scale_slot_ = active_scale_slot_;
-      }
     }
     else if (prev_scale_slot_ != get_scale_select()) {
       active_scale_slot_ = get_scale_select();
@@ -504,6 +506,7 @@ public:
             // if scale changes, we have to update the root and transpose values, too; mask gets updated in update_scale
             root = get_root(display_scale_slot_);
             transpose = get_transpose(display_scale_slot_);
+            schedule_scale_update_ = true;
           break;
           case DQ_DEST_ROOT:
               root += (OC::ADC::value(static_cast<ADC_CHANNEL>(channel_id)) + 127) >> 8;
@@ -519,7 +522,12 @@ public:
           break;
           default:
           break;
-        } // end switch  
+        } // end switch
+        
+        if (schedule_scale_update_) {
+          force_update_ = true;
+          schedule_scale_update_ = false;
+        }
       } // -> triggered update
 
       // constrain values: 
@@ -658,7 +666,7 @@ public:
 
           // update scale?
           if (schedule_scale_update_ && _continuous_update) {
-            update_scale(false, display_scale_slot_, schedule_mask_rotate_);
+            update_scale(true, display_scale_slot_, schedule_mask_rotate_);
             schedule_scale_update_ = false;
           }  
 
@@ -1046,7 +1054,7 @@ private:
     force_update_ = false;  
     const int scale = get_scale(scale_select);
     uint16_t mask = get_mask(scale_select);
-    
+
     if (mask_rotate)
       mask = OC::ScaleEditor<DQ_QuantizerChannel>::RotateMask(mask, OC::Scales::GetScale(scale).num_notes, mask_rotate);
       
@@ -1389,6 +1397,7 @@ void DQ_handleEncoderEvent(const UI::Event &event) {
             dq_state.cursor.AdjustEnd(selected.num_enabled_settings() - 1);
           break;
           case DQ_CHANNEL_SETTING_SCALE_SEQ:
+          case DQ_CHANNEL_SETTING_SEQ_MODE:
             selected.update_enabled_settings();
             dq_state.cursor.AdjustEnd(selected.num_enabled_settings() - 1);
             selected.reset_scale();
diff --git a/software/o_c_REV/APP_ENVGEN.ino b/software/o_c_REV/APP_ENVGEN.ino
index f8ed3695..0647aec9 100644
--- a/software/o_c_REV/APP_ENVGEN.ino
+++ b/software/o_c_REV/APP_ENVGEN.ino
@@ -446,7 +446,11 @@ public:
     CONSTRAIN(s[CV_MAPPING_EUCLIDEAN_FILL], 0, 32);
     CONSTRAIN(s[CV_MAPPING_EUCLIDEAN_OFFSET], 0, 32);
     CONSTRAIN(s[CV_MAPPING_DELAY_MSEC], 0, 65535);
+ #ifdef VOR
+    CONSTRAIN(s[CV_MAPPING_AMPLITUDE], 0, 62850);
+ #else 
     CONSTRAIN(s[CV_MAPPING_AMPLITUDE], 0, 65535);
+ #endif
     CONSTRAIN(s[CV_MAPPING_MAX_LOOPS], 0, 65535);
 
     EnvelopeType type = get_type();
diff --git a/software/o_c_REV/APP_QQ.ino b/software/o_c_REV/APP_QQ.ino
index 85fa1ab9..fa115ae1 100644
--- a/software/o_c_REV/APP_QQ.ino
+++ b/software/o_c_REV/APP_QQ.ino
@@ -953,7 +953,8 @@ public:
         *settings++ = CHANNEL_SETTING_TURING_RANGE;
         *settings++ = CHANNEL_SETTING_TURING_PROB;
         if (OC::Scales::SCALE_NONE != get_scale(DUMMY))
-            *settings++ = CHANNEL_SETTING_TURING_RANGE_CV_SOURCE;
+            *settings++ = CHANNEL_SETTING_TURING_MODULUS_CV_SOURCE;
+        *settings++ = CHANNEL_SETTING_TURING_RANGE_CV_SOURCE;
         *settings++ = CHANNEL_SETTING_TURING_PROB_CV_SOURCE;
       break;
       case CHANNEL_SOURCE_LOGISTIC_MAP:
@@ -1565,4 +1566,3 @@ void QQ_debug() {
  }
 }
 #endif // QQ_DEBUG
-
diff --git a/software/o_c_REV/APP_REFS.ino b/software/o_c_REV/APP_REFS.ino
index e800eeed..8366b202 100644
--- a/software/o_c_REV/APP_REFS.ino
+++ b/software/o_c_REV/APP_REFS.ino
@@ -596,6 +596,8 @@ const char* const error[] = {
 SETTINGS_DECLARE(ReferenceChannel, REF_SETTING_LAST) {
   #ifdef BUCHLA_4U
   { 0, 0, 9, "Octave", nullptr, settings::STORAGE_TYPE_I8 },
+  #elif defined(VOR) 
+  {0, 0, 10, "Octave", nullptr, settings::STORAGE_TYPE_I8 },
   #else
   { 0, -3, 6, "Octave", nullptr, settings::STORAGE_TYPE_I8 },
   #endif
diff --git a/software/o_c_REV/OC_DAC.cpp b/software/o_c_REV/OC_DAC.cpp
index a3029f34..c1e0b8db 100644
--- a/software/o_c_REV/OC_DAC.cpp
+++ b/software/o_c_REV/OC_DAC.cpp
@@ -54,13 +54,21 @@ void DAC::Init(CalibrationData *calibration_data) {
 
   // set up DAC pins 
   OC::pinMode(DAC_CS, OUTPUT);
-  OC::pinMode(DAC_RST,OUTPUT);
   
+  #ifndef VOR
+  OC::pinMode(DAC_RST,OUTPUT);
   #ifdef DAC8564 // A0 = 0, A1 = 0
     digitalWrite(DAC_RST, LOW); 
   #else  // default to DAC8565 - pull RST high 
     digitalWrite(DAC_RST, HIGH);
   #endif
+  #endif
+
+#ifdef VOR
+  // set Vbias, using onboard DAC:
+  init_Vbias();
+  delay(10);
+#endif
 
   history_tail_ = 0;
   memset(history_, 0, sizeof(uint16_t) * kHistoryDepth * DAC_CHANNEL_LAST);
@@ -185,6 +193,7 @@ void DAC::restore_scaling(uint32_t scaling) {
     set_scaling(_scaling, i);
   }
 }
+/*static*/
 uint32_t DAC::store_scaling() {
 
   uint32_t _scaling = 0;
@@ -193,6 +202,17 @@ uint32_t DAC::store_scaling() {
     _scaling |= (DAC_scaling[i] << (i * 8)); 
   return _scaling;
 }
+/*static*/ 
+void DAC::init_Vbias() {
+  /* using MK20 DAC0 for Vbias*/
+  VREF_TRM = 0x60; VREF_SC = 0xE1; // enable 1v2 reference
+  SIM_SCGC2 |= SIM_SCGC2_DAC0; // DAC clock
+  DAC0_C0 = DAC_C0_DACEN; // enable module + use internal 1v2 reference
+}
+/*static*/ 
+void DAC::set_Vbias(uint32_t data) {
+  *(volatile int16_t *)&(DAC0_DAT0L) = data;
+}
 /*static*/
 DAC::CalibrationData *DAC::calibration_data_ = nullptr;
 /*static*/
diff --git a/software/o_c_REV/OC_DAC.h b/software/o_c_REV/OC_DAC.h
index 219b1a8e..a9038b6c 100644
--- a/software/o_c_REV/OC_DAC.h
+++ b/software/o_c_REV/OC_DAC.h
@@ -41,6 +41,11 @@ class DAC {
 
   #ifdef BUCHLA_4U
     static constexpr int kOctaveZero = 0;
+  #elif defined(VOR) 
+    static constexpr int kOctaveZero = 0;
+    static constexpr int VBiasUnipolar = 3900;   // onboard DAC @ Vref 1.2V (internal), 1.75x gain
+    static constexpr int VBiasBipolar = 2000;    // onboard DAC @ Vref 1.2V (internal), 1.75x gain
+    static constexpr int VBiasAsymmetric = 2760; // onboard DAC @ Vref 1.2V (internal), 1.75x gain
   #else
     static constexpr int kOctaveZero = 3;
   #endif
@@ -62,6 +67,8 @@ class DAC {
   static void restore_scaling(uint32_t scaling);
   static uint8_t get_voltage_scaling(uint8_t channel_id);
   static uint32_t store_scaling();
+  static void set_Vbias(uint32_t data);
+  static void init_Vbias();
   
   static void set_all(uint32_t value) {
     for (int i = DAC_CHANNEL_A; i < DAC_CHANNEL_LAST; ++i)
diff --git a/software/o_c_REV/OC_apps.ino b/software/o_c_REV/OC_apps.ino
index 060fd954..8388e98e 100644
--- a/software/o_c_REV/OC_apps.ino
+++ b/software/o_c_REV/OC_apps.ino
@@ -207,6 +207,11 @@ void restore_app_data() {
     }
     restored_bytes += chunk->length;
     data += chunk->length;
+    
+#ifdef VOR
+    VBiasManager *vbias_m = vbias_m->get();
+    vbias_m->SetStateForApp(apps::index_of(global_settings.current_app_id));
+#endif
   }
 
   SERIAL_PRINTLN("App data restored: %u, expected %u", restored_bytes, app_settings.used);
@@ -407,6 +412,10 @@ void Ui::AppSettings() {
   // Restore state
   apps::current_app->HandleAppEvent(APP_EVENT_RESUME);
   CORE::app_isr_enabled = true;
+#ifdef VOR
+  VBiasManager *vbias_m = vbias_m->get();
+  vbias_m->SetStateForApp(apps::index_of(global_settings.current_app_id));
+#endif
 }
 
 bool Ui::ConfirmReset() {
diff --git a/software/o_c_REV/OC_autotuner.h b/software/o_c_REV/OC_autotuner.h
index dd33d780..2b8c526b 100644
--- a/software/o_c_REV/OC_autotuner.h
+++ b/software/o_c_REV/OC_autotuner.h
@@ -12,6 +12,10 @@ const char* const AT_steps[] = {
 const char* const AT_steps[] = {
   "0.0V", "1.0V", "2.0V", "3.0V", "4.0V", "5.0V", "6.0V", "7.0V", "8.0V", "9.0V", " " 
 };
+#elif defined(VOR)
+const char* const AT_steps[] = {
+  "0.0V", "1.0V", "2.0V", "3.0V", "4.0V", "5.0V", "6.0V", "7.0V", "8.0V", "9.0V", "10.0V", " " 
+};
 #else
 const char* const AT_steps[] = {
   "-3V", "-2V", "-1V", " 0V", "+1V", "+2V", "+3V", "+4V", "+5V", "+6V", " " 
diff --git a/software/o_c_REV/OC_calibration.h b/software/o_c_REV/OC_calibration.h
index fa61a22b..5ae0fd73 100644
--- a/software/o_c_REV/OC_calibration.h
+++ b/software/o_c_REV/OC_calibration.h
@@ -2,8 +2,9 @@
 #define OC_CALIBRATION_H_
 
 #include "OC_ADC.h"
-#include "OC_config.h"
 #include "OC_DAC.h"
+#include "OC_config.h"
+#include "OC_options.h"
 #include "util/util_pagestorage.h"
 #include "util/EEPROMStorage.h"
 
@@ -44,7 +45,12 @@ struct CalibrationData {
   uint32_t flags;
   uint8_t screensaver_timeout; // 0: default, else seconds
   uint8_t reserved0[3];
-  uint32_t reserved1;
+  #ifdef VOR
+    /* less complicated this way than adding it to DAC::CalibrationData... */
+    uint32_t v_bias; // upper 2 bytes: asymmetric; lower 2 bytes: bipolar.
+  #else
+    uint32_t reserved1;
+  #endif
 
   EncoderConfig encoder_config() const {
   	return static_cast<EncoderConfig>(flags & CALIBRATION_FLAG_ENCODER_MASK);
diff --git a/software/o_c_REV/OC_calibration.ino b/software/o_c_REV/OC_calibration.ino
index ad7a8ad3..b76cd44d 100644
--- a/software/o_c_REV/OC_calibration.ino
+++ b/software/o_c_REV/OC_calibration.ino
@@ -10,7 +10,7 @@
 
 using OC::DAC;
 
-#ifdef BUCHLA_cOC
+#if defined(BUCHLA_cOC) || defined(VOR)
 static constexpr uint16_t DAC_OFFSET = 0;  // DAC offset, initial approx., ish (Easel card)
 #else
 static constexpr uint16_t DAC_OFFSET = 4890; // DAC offset, initial approx., ish --> -3.5V to 6V
@@ -38,6 +38,11 @@ const OC::CalibrationData kCalibrationDefaults = {
     {197, 6634, 13083, 19517, 25966, 32417, 38850, 45301, 51733, 58180, 64400},
     {197, 6634, 13083, 19517, 25966, 32417, 38850, 45301, 51733, 58180, 64400},
     {197, 6634, 13083, 19517, 25966, 32417, 38850, 45301, 51733, 58180, 64400}
+    #elif defined(VOR)
+    {880, 7190, 13510, 19830, 26300, 32460, 38770, 45090, 51410, 57720, 64040},
+    {880, 7190, 13510, 19830, 26300, 32460, 38770, 45090, 51410, 57720, 64040},
+    {880, 7190, 13510, 19830, 26300, 32460, 38770, 45090, 51410, 57720, 64040},
+    {880, 7190, 13510, 19830, 26300, 32460, 38770, 45090, 51410, 57720, 64040}
     #else
     {0, 6553, 13107, 19661, 26214, 32768, 39321, 45875, 52428, 58981, 65535},
     {0, 6553, 13107, 19661, 26214, 32768, 39321, 45875, 52428, 58981, 65535},
@@ -54,8 +59,13 @@ const OC::CalibrationData kCalibrationDefaults = {
   // display_offset
   SH1106_128x64_Driver::kDefaultOffset,
   OC_CALIBRATION_DEFAULT_FLAGS,
-  SCREENSAVER_TIMEOUT_S, { 0, 0, 0 },
-  0 // reserved
+  SCREENSAVER_TIMEOUT_S, 
+  { 0, 0, 0 }, // reserved0
+  #ifdef VOR
+  DAC::VBiasBipolar | (DAC::VBiasAsymmetric << 16) // default v_bias values
+  #else
+  0 // reserved1
+  #endif
 };
 
 void calibration_reset() {
@@ -107,12 +117,20 @@ void calibration_save() {
 enum CALIBRATION_STEP {  
   HELLO,
   CENTER_DISPLAY,
-
+  
+  #ifdef VOR
+  DAC_A_VOLT_3m, DAC_A_VOLT_2m, DAC_A_VOLT_1m, DAC_A_VOLT_0, DAC_A_VOLT_1, DAC_A_VOLT_2, DAC_A_VOLT_3, DAC_A_VOLT_4, DAC_A_VOLT_5, DAC_A_VOLT_6, DAC_A_VOLT_7,
+  DAC_B_VOLT_3m, DAC_B_VOLT_2m, DAC_B_VOLT_1m, DAC_B_VOLT_0, DAC_B_VOLT_1, DAC_B_VOLT_2, DAC_B_VOLT_3, DAC_B_VOLT_4, DAC_B_VOLT_5, DAC_B_VOLT_6, DAC_B_VOLT_7,
+  DAC_C_VOLT_3m, DAC_C_VOLT_2m, DAC_C_VOLT_1m, DAC_C_VOLT_0, DAC_C_VOLT_1, DAC_C_VOLT_2, DAC_C_VOLT_3, DAC_C_VOLT_4, DAC_C_VOLT_5, DAC_C_VOLT_6, DAC_C_VOLT_7,
+  DAC_D_VOLT_3m, DAC_D_VOLT_2m, DAC_D_VOLT_1m, DAC_D_VOLT_0, DAC_D_VOLT_1, DAC_D_VOLT_2, DAC_D_VOLT_3, DAC_D_VOLT_4, DAC_D_VOLT_5, DAC_D_VOLT_6, DAC_D_VOLT_7,
+  V_BIAS_BIPOLAR, V_BIAS_ASYMMETRIC,
+  #else
   DAC_A_VOLT_3m, DAC_A_VOLT_2m, DAC_A_VOLT_1m, DAC_A_VOLT_0, DAC_A_VOLT_1, DAC_A_VOLT_2, DAC_A_VOLT_3, DAC_A_VOLT_4, DAC_A_VOLT_5, DAC_A_VOLT_6,
   DAC_B_VOLT_3m, DAC_B_VOLT_2m, DAC_B_VOLT_1m, DAC_B_VOLT_0, DAC_B_VOLT_1, DAC_B_VOLT_2, DAC_B_VOLT_3, DAC_B_VOLT_4, DAC_B_VOLT_5, DAC_B_VOLT_6,
   DAC_C_VOLT_3m, DAC_C_VOLT_2m, DAC_C_VOLT_1m, DAC_C_VOLT_0, DAC_C_VOLT_1, DAC_C_VOLT_2, DAC_C_VOLT_3, DAC_C_VOLT_4, DAC_C_VOLT_5, DAC_C_VOLT_6,
   DAC_D_VOLT_3m, DAC_D_VOLT_2m, DAC_D_VOLT_1m, DAC_D_VOLT_0, DAC_D_VOLT_1, DAC_D_VOLT_2, DAC_D_VOLT_3, DAC_D_VOLT_4, DAC_D_VOLT_5, DAC_D_VOLT_6,
-
+  #endif
+  
   CV_OFFSET_0, CV_OFFSET_1, CV_OFFSET_2, CV_OFFSET_3,
   ADC_PITCH_C2, ADC_PITCH_C4,
   CALIBRATION_SCREENSAVER_TIMEOUT,
@@ -124,6 +142,10 @@ enum CALIBRATION_STEP {
 enum CALIBRATION_TYPE {
   CALIBRATE_NONE,
   CALIBRATE_OCTAVE,
+  #ifdef VOR
+  CALIBRATE_VBIAS_BIPOLAR,
+  CALIBRATE_VBIAS_ASYMMETRIC,
+  #endif
   CALIBRATE_ADC_OFFSET,
   CALIBRATE_ADC_1V,
   CALIBRATE_ADC_3V,
@@ -149,7 +171,8 @@ DAC_CHANNEL step_to_channel(int step) {
   if (step >= DAC_D_VOLT_3m) return DAC_CHANNEL_D;
   if (step >= DAC_C_VOLT_3m) return DAC_CHANNEL_C;
   if (step >= DAC_B_VOLT_3m) return DAC_CHANNEL_B;
-  /*if (step >= DAC_B_VOLT_3m)*/ return DAC_CHANNEL_A;
+  /*if (step >= DAC_B_VOLT_3m)*/ 
+  return DAC_CHANNEL_A;
 }
 
 struct CalibrationState {
@@ -161,7 +184,7 @@ struct CalibrationState {
 
   uint16_t adc_1v;
   uint16_t adc_3v;
-
+  
   bool used_defaults;
 };
 
@@ -222,7 +245,7 @@ const CalibrationStep calibration_steps[CALIBRATION_STEP_LAST] = {
     { DAC_D_VOLT_4,  "DAC D 8.4 volts", "-> 8.400V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
     { DAC_D_VOLT_5,  "DAC D 9.6 volts", "-> 9.600V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
     { DAC_D_VOLT_6,  "DAC D 10.8 volts", "-> 10.800V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
-  #elif defined(IO_10V)
+  #elif defined(IO_10V) && !defined(VOR)
     { DAC_A_VOLT_3m, "DAC A 0.0 volts", "-> 0.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 0, nullptr, 0, DAC::MAX_VALUE },
     { DAC_A_VOLT_2m, "DAC A 1.0 volts", "-> 1.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 1, nullptr, 0, DAC::MAX_VALUE },
     { DAC_A_VOLT_1m, "DAC A 2.0 volts", "-> 2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 2, nullptr, 0, DAC::MAX_VALUE },
@@ -266,6 +289,54 @@ const CalibrationStep calibration_steps[CALIBRATION_STEP_LAST] = {
     { DAC_D_VOLT_4,  "DAC D 7.0 volts", "-> 7.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
     { DAC_D_VOLT_5,  "DAC D 8.0 volts", "-> 8.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
     { DAC_D_VOLT_6,  "DAC D 9.0 volts", "-> 9.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
+  #elif defined(VOR)
+    { DAC_A_VOLT_3m, "DAC A  0.0 volts", "-> 0.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 0, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_2m, "DAC A  1.0 volts", "-> 1.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 1, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_1m, "DAC A  2.0 volts", "-> 2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 2, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_0,  "DAC A  3.0 volts", "-> 3.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 3, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_1,  "DAC A  4.0 volts", "-> 4.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 4, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_2,  "DAC A  5.0 volts", "-> 5.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 5, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_3,  "DAC A  6.0 volts", "-> 6.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 6, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_4,  "DAC A  7.0 volts", "-> 7.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_5,  "DAC A  8.0 volts", "-> 8.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_6,  "DAC A  9.0 volts", "-> 9.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_A_VOLT_7,  "DAC A 10.0 volts", "-> 10.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 10, nullptr, 0, DAC::MAX_VALUE },
+    
+    { DAC_B_VOLT_3m, "DAC B  0.0 volts", "-> 0.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 0, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_2m, "DAC B  1.0 volts", "-> 1.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 1, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_1m, "DAC B  2.0 volts", "-> 2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 2, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_0,  "DAC B  3.0 volts", "-> 3.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 3, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_1,  "DAC B  4.0 volts", "-> 4.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 4, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_2,  "DAC B  5.0 volts", "-> 5.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 5, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_3,  "DAC B  6.0 volts", "-> 6.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 6, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_4,  "DAC B  7.0 volts", "-> 7.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_5,  "DAC B  8.0 volts", "-> 8.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_6,  "DAC B  9.0 volts", "-> 9.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_B_VOLT_7,  "DAC B 10.0 volts", "-> 10.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 10, nullptr, 0, DAC::MAX_VALUE },
+  
+    { DAC_C_VOLT_3m, "DAC C  0.0 volts", "-> 0.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 0, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_2m, "DAC C  1.0 volts", "-> 1.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 1, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_1m, "DAC C  2.0 volts", "-> 2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 2, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_0,  "DAC C  3.0 volts", "-> 3.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 3, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_1,  "DAC C  4.0 volts", "-> 4.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 4, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_2,  "DAC C  5.0 volts", "-> 5.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 5, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_3,  "DAC C  6.0 volts", "-> 6.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 6, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_4,  "DAC C  7.0 volts", "-> 7.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_5,  "DAC C  8.0 volts", "-> 8.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_6,  "DAC C  9.0 volts", "-> 9.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_C_VOLT_7,  "DAC C 10.0 volts", "-> 10.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 10, nullptr, 0, DAC::MAX_VALUE },
+  
+    { DAC_D_VOLT_3m, "DAC D  0.0 volts", "-> 0.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 0, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_2m, "DAC D  1.0 volts", "-> 1.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 1, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_1m, "DAC D  2.0 volts", "-> 2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 2, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_0,  "DAC D  3.0 volts", "-> 3.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 3, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_1,  "DAC D  4.0 volts", "-> 4.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 4, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_2,  "DAC D  5.0 volts", "-> 5.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 5, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_3,  "DAC D  6.0 volts", "-> 6.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 6, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_4,  "DAC D  7.0 volts", "-> 7.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 7, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_5,  "DAC D  8.0 volts", "-> 8.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 8, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_6,  "DAC D  9.0 volts", "-> 9.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 9, nullptr, 0, DAC::MAX_VALUE },
+    { DAC_D_VOLT_7,  "DAC D 10.0 volts", "-> 10.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 10, nullptr, 0, DAC::MAX_VALUE },
   #else
     { DAC_A_VOLT_3m, "DAC A -3 volts", "-> -3.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, -3, nullptr, 0, DAC::MAX_VALUE },
     { DAC_A_VOLT_2m, "DAC A -2 volts", "-> -2.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, -2, nullptr, 0, DAC::MAX_VALUE },
@@ -311,6 +382,11 @@ const CalibrationStep calibration_steps[CALIBRATION_STEP_LAST] = {
     { DAC_D_VOLT_5,  "DAC D 5 volts", "->  5.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 5, nullptr, 0, DAC::MAX_VALUE },
     { DAC_D_VOLT_6,  "DAC D 6 volts", "->  6.000V ", default_help_r, default_footer, CALIBRATE_OCTAVE, 6, nullptr, 0, DAC::MAX_VALUE },
   #endif
+
+  #ifdef VOR
+    { V_BIAS_BIPOLAR, "0.000V: bipolar", "--> 0.000V", default_help_r, default_footer, CALIBRATE_VBIAS_BIPOLAR, 0, nullptr, 0, 4095 },
+    { V_BIAS_ASYMMETRIC, "0.000V: asym.", "--> 0.000V", default_help_r, default_footer, CALIBRATE_VBIAS_ASYMMETRIC, 0, nullptr, 0, 4095 },
+  #endif
   
   { CV_OFFSET_0, "ADC CV1", "ADC value at 0V", default_help_r, default_footer, CALIBRATE_ADC_OFFSET, ADC_CHANNEL_1, nullptr, 0, 4095 },
   { CV_OFFSET_1, "ADC CV2", "ADC value at 0V", default_help_r, default_footer, CALIBRATE_ADC_OFFSET, ADC_CHANNEL_2, nullptr, 0, 4095 },
@@ -441,13 +517,23 @@ void OC::Ui::Calibrate() {
         calibration_state.encoder_value =
             OC::calibration_data.dac.calibrated_octaves[step_to_channel(next_step->step)][next_step->index + DAC::kOctaveZero];
         break;
+
+      #ifdef VOR
+      case CALIBRATE_VBIAS_BIPOLAR:
+        calibration_state.encoder_value = (0xFFFF & OC::calibration_data.v_bias); // bipolar = lower 2 bytes
+      break;
+      case CALIBRATE_VBIAS_ASYMMETRIC:
+        calibration_state.encoder_value = (OC::calibration_data.v_bias >> 16);  // asymmetric = upper 2 bytes
+      break;
+      #endif
+      
       case CALIBRATE_ADC_OFFSET:
         calibration_state.encoder_value = OC::calibration_data.adc.offset[next_step->index];
         break;
       case CALIBRATE_DISPLAY:
         calibration_state.encoder_value = OC::calibration_data.display_offset;
         break;
-
+        
       case CALIBRATE_ADC_1V:
       case CALIBRATE_ADC_3V:
         SERIAL_PRINTLN("offset=%d", OC::calibration_data.adc.offset[ADC_CHANNEL_1]);
@@ -502,6 +588,10 @@ void calibration_draw(const CalibrationState &state) {
   switch (step->calibration_type) {
     case CALIBRATE_OCTAVE:
     case CALIBRATE_SCREENSAVER:
+    #ifdef VOR
+    case CALIBRATE_VBIAS_BIPOLAR:
+    case CALIBRATE_VBIAS_ASYMMETRIC:
+    #endif
       graphics.print(step->message);
       graphics.setPrintPos(kValueX, y + 2);
       graphics.print((int)state.encoder_value, 5);
@@ -594,10 +684,32 @@ void calibration_update(CalibrationState &state) {
       OC::calibration_data.dac.calibrated_octaves[step_to_channel(step->step)][step->index + DAC::kOctaveZero] =
         state.encoder_value;
       DAC::set_all_octave(step->index);
+      #ifdef VOR
+      /* set 0V @ unipolar range */
+      DAC::set_Vbias(DAC::VBiasUnipolar);
+      #endif
+      break;
+    #ifdef VOR
+    case CALIBRATE_VBIAS_BIPOLAR:
+      /* set 0V @ bipolar range */
+      DAC::set_all_octave(5);
+      OC::calibration_data.v_bias = (OC::calibration_data.v_bias & 0xFFFF0000) | state.encoder_value;
+      DAC::set_Vbias(0xFFFF & OC::calibration_data.v_bias);
       break;
+    case CALIBRATE_VBIAS_ASYMMETRIC:
+      /* set 0V @ asym. range */
+      DAC::set_all_octave(3);
+      OC::calibration_data.v_bias = (OC::calibration_data.v_bias & 0xFFFF) | (state.encoder_value << 16);
+      DAC::set_Vbias(OC::calibration_data.v_bias >> 16);
+    break;
+    #endif
     case CALIBRATE_ADC_OFFSET:
       OC::calibration_data.adc.offset[step->index] = state.encoder_value;
       DAC::set_all_octave(0);
+      #ifdef VOR
+      /* set 0V @ unipolar range */
+      DAC::set_Vbias(DAC::VBiasUnipolar);
+      #endif
       break;
     case CALIBRATE_ADC_1V:
       DAC::set_all_octave(1);
@@ -626,42 +738,4 @@ uint32_t adc_average() {
     OC::ADC::smoothed_raw_value(ADC_CHANNEL_3) + OC::ADC::smoothed_raw_value(ADC_CHANNEL_4);
 }
 
-#ifdef CALIBRATION_LOAD_LEGACY
-/* read settings from original O&C */
-void calibration_read_old() {
-  
-   delay(1000);
-   uint8_t byte0, byte1, adr;
-   
-   adr = 0; 
-   SERIAL_PRINTLN("Loading original O&C calibration from eeprom:");
-   
-   for (int i = 0; i < OCTAVES; i++) {  
-  
-       byte0 = EEPROM.read(adr);
-       adr++;
-       byte1 = EEPROM.read(adr);
-       adr++;
-       OC::calibration_data.dac.octaves[i] = (uint16_t)(byte0 << 8) + byte1;
-       SERIAL_PRINTLN(" OCTAVE %2d: %u", i, OC::calibration_data.dac.octaves[i]);
-   }
-   
-   uint16_t _offset[ADC_CHANNEL_LAST];
-   
-   for (int i = 0; i < ADC_CHANNEL_LAST; i++) {  
-  
-       byte0 = EEPROM.read(adr);
-       adr++;
-       byte1 = EEPROM.read(adr);
-       adr++;
-       _offset[i] = (uint16_t)(byte0 << 8) + byte1;
-       SERIAL_PRINTLN("ADC %d: %u", i, _offset[i]);
-   }
-   
-   OC::calibration_data.adc.offset[ADC_CHANNEL_1] = _offset[0];
-   OC::calibration_data.adc.offset[ADC_CHANNEL_2] = _offset[1];
-   OC::calibration_data.adc.offset[ADC_CHANNEL_3] = _offset[2];
-   OC::calibration_data.adc.offset[ADC_CHANNEL_4] = _offset[3];
-   SERIAL_PRINTLN("......");
-}  
-#endif
+// end
diff --git a/software/o_c_REV/OC_gpio.h b/software/o_c_REV/OC_gpio.h
index 5c6b25f9..c9e14446 100644
--- a/software/o_c_REV/OC_gpio.h
+++ b/software/o_c_REV/OC_gpio.h
@@ -39,9 +39,14 @@
 #define OLED_CS_ACTIVE LOW
 #define OLED_CS_INACTIVE HIGH
 
-#define DAC_RST 9
 #define DAC_CS 10
 
+#ifdef VOR
+  #define but_mid 9
+#else
+  #define DAC_RST 9
+#endif
+
 // NOTE: encoder pins R1/R2 changed for rev >= 2c
 #ifdef FLIP_180
   #define encL1 16
diff --git a/software/o_c_REV/OC_options.h b/software/o_c_REV/OC_options.h
index 10fc13d6..bc884293 100644
--- a/software/o_c_REV/OC_options.h
+++ b/software/o_c_REV/OC_options.h
@@ -7,27 +7,39 @@
 #ifndef OC_OPTIONS_H_
 #define OC_OPTIONS_H_
 
-/* ------------ uncomment for Buchla/non-octaval/quartertone support: -------------------------------  */
+/* ------------ uncomment for use with Plum Audio VOR anabled versions (OCP, 1uO_c v2, 4Robots) ---------------------------------------------------------  */
+//#define VOR
+/* ------------ uncomment for use with Plum Audio 1uO_c 4Robots (To use Up button long press to change VOR instead activate screensaver) ----------------  */
+//#define VOR_NO_RANGE_BUTTON
+
+/* ------------ uncomment for Buchla/non-octaval/quartertone support: ----------------------------------------------------------------------------------- */
 //#define BUCHLA_SUPPORT
-/* ------------ uncomment for use with Northernlight cOC program card: ------------------------------  */
+/* ------------ uncomment for use with Northernlight cOC program card: ----------------------------------------------------------------------------------  */
 //#define BUCHLA_cOC
-/* ------------ uncomment for use with Northernlight 4U / cOC : -------------------------------------  */
+/* ------------ uncomment for use with Northernlight 4U / cOC : -----------------------------------------------------------------------------------------  */
 //#define BUCHLA_4U
-/* ------------ uncomment for boring app names ------------------------------------------------------  */
+/* ------------ uncomment for boring app names ----------------------------------------------------------------------------------------------------------  */
 //#define BORING_APP_NAMES
-/* ------------ print debug messages to USB serial --------------------------------------------------  */
+/* ------------ print debug messages to USB serial ------------------------------------------------------------------------------------------------------  */
 //#define PRINT_DEBUG
-/* ------------ flip screen / IO mapping ------------------------------------------------------------  */
+/* ------------ flip screen / IO mapping ----------------------------------------------------------------------------------------------------------------  */
 //#define FLIP_180
-/* ------------ invert screen pixels ----------------------------------------------------------------  */
+/* ------------ invert screen pixels --------------------------------------------------------------------------------------------------------------------  */
 //#define INVERT_DISPLAY
-/* ------------ use DAC8564 -------------------------------------------------------------------------  */
+/* ------------ use DAC8564 -----------------------------------------------------------------------------------------------------------------------------  */
 //#define DAC8564
-/* ------------ 0 / 10V range -----------------------------------------------------------------------  */
+/* ------------ 0 / 10V range ---------------------------------------------------------------------------------------------------------------------------  */
 //#define IO_10V
 
+
+/* do not edit the stuff below (unless ... ) */
+
 #if defined(IO_10V)
   #define BUCHLA_4U
 #endif
 
+#if defined(VOR)
+  #define IO_10V
+#endif
+
 #endif
diff --git a/software/o_c_REV/OC_scale_edit.h b/software/o_c_REV/OC_scale_edit.h
index 59544561..2e0f7242 100644
--- a/software/o_c_REV/OC_scale_edit.h
+++ b/software/o_c_REV/OC_scale_edit.h
@@ -628,11 +628,15 @@ template <typename Owner>
 void ScaleEditor<Owner>::BeginEditing(bool mode) {
 
   cursor_pos_ = 0;
-  num_notes_ = scale_->num_notes;
-  mask_ = owner_->get_scale_mask(DUMMY);
+  num_notes_ = scale_->num_notes; 
+   
   if (mode) { // == meta-Q
     edit_this_scale_ = owner_->get_scale_select();
-   OC::ui._preemptScreensaver(true);
+    mask_ = owner_->get_scale_mask(edit_this_scale_);
+    OC::ui._preemptScreensaver(true);
+  }
+  else { 
+    mask_ = owner_->get_scale_mask(DUMMY); 
   }
 }
 
diff --git a/software/o_c_REV/OC_strings.cpp b/software/o_c_REV/OC_strings.cpp
index e96f2c7b..37a01135 100644
--- a/software/o_c_REV/OC_strings.cpp
+++ b/software/o_c_REV/OC_strings.cpp
@@ -16,6 +16,8 @@ namespace OC {
   
   const char * const note_names_unpadded[12] = { "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" };
 
+  const char * const VOR_offsets[3] = { "-5V", "-3V", "0V"};
+
   const char * const trigger_input_names[4] = { "TR1", "TR2", "TR3", "TR4" };
 
   const char * const trigger_input_names_none[5] = { " - ", "TR1", "TR2", "TR3", "TR4" };
diff --git a/software/o_c_REV/OC_strings.h b/software/o_c_REV/OC_strings.h
index d69a7d9d..41bac207 100644
--- a/software/o_c_REV/OC_strings.h
+++ b/software/o_c_REV/OC_strings.h
@@ -17,6 +17,7 @@ namespace OC {
     extern const char * const channel_id[];
     extern const char * const note_names[];
     extern const char * const note_names_unpadded[];
+    extern const char * const VOR_offsets[];    
     extern const char * const trigger_input_names[];
     extern const char * const trigger_input_names_none[];
     extern const char * const cv_input_names[];
diff --git a/software/o_c_REV/OC_ui.cpp b/software/o_c_REV/OC_ui.cpp
index bb405fd1..b8b6ea08 100644
--- a/software/o_c_REV/OC_ui.cpp
+++ b/software/o_c_REV/OC_ui.cpp
@@ -14,6 +14,11 @@
 #include "OC_options.h"
 #include "src/drivers/display.h"
 
+#ifdef VOR
+#include "VBiasManager.h"
+VBiasManager *VBiasManager::instance = 0;
+#endif
+
 extern uint_fast8_t MENU_REDRAW;
 
 namespace OC {
@@ -24,7 +29,12 @@ void Ui::Init() {
   ticks_ = 0;
   set_screensaver_timeout(SCREENSAVER_TIMEOUT_S);
 
+  #ifdef VOR
+  static const int button_pins[] = { but_top, but_bot, butL, butR, but_mid };
+  #else
   static const int button_pins[] = { but_top, but_bot, butL, butR };
+  #endif
+  
   for (size_t i = 0; i < CONTROL_BUTTON_LAST; ++i) {
     buttons_[i].Init(button_pins[i], OC_GPIO_BUTTON_PINMODE);
   }
@@ -111,12 +121,31 @@ UiMode Ui::DispatchEvents(App *app) {
 
     switch (event.type) {
       case UI::EVENT_BUTTON_PRESS:
+        #ifdef VOR
+          #ifdef VOR_NO_RANGE_BUTTON
+        if (OC::CONTROL_BUTTON_UP == event.control) {
+            VBiasManager *vbias_m = vbias_m->get();
+            if (vbias_m->IsEditing()) vbias_m->AdvanceBias();
+            else app->HandleButtonEvent(event);
+        } else app->HandleButtonEvent(event);
+          #else
+        if (OC::CONTROL_BUTTON_M == event.control) {
+            VBiasManager *vbias_m = vbias_m->get();
+            vbias_m->AdvanceBias();
+        } else app->HandleButtonEvent(event);
+        #endif
+        #else
         app->HandleButtonEvent(event);
+        #endif
         break;
       case UI::EVENT_BUTTON_LONG_PRESS:
         if (OC::CONTROL_BUTTON_UP == event.control) {
-          if (!preempt_screensaver_) 
-            screensaver_ = true;
+        #ifdef VOR_NO_RANGE_BUTTON
+            VBiasManager *vbias_m = vbias_m->get();
+            vbias_m->AdvanceBias();
+        #else
+            if (!preempt_screensaver_) screensaver_ = true;
+        #endif
         }
         else if (OC::CONTROL_BUTTON_R == event.control)
           return UI_MODE_APP_SETTINGS;
@@ -169,6 +198,8 @@ UiMode Ui::Splashscreen(bool &reset_settings) {
     menu::DefaultTitleBar::Draw();
     #ifdef BUCHLA_cOC
       graphics.print("NLM card O_C");
+    #elif defined(VOR)
+      graphics.print("Plum Audio O_C+");
     #else
       graphics.print("Ornaments & Crimes");
     #endif
diff --git a/software/o_c_REV/OC_ui.h b/software/o_c_REV/OC_ui.h
index 77ad4405..cbc456c0 100644
--- a/software/o_c_REV/OC_ui.h
+++ b/software/o_c_REV/OC_ui.h
@@ -2,6 +2,7 @@
 #define OC_UI_H_
 
 #include "OC_config.h"
+#include "OC_options.h"
 #include "OC_debug.h"
 #include "UI/ui_button.h"
 #include "UI/ui_encoder.h"
@@ -19,13 +20,18 @@ enum UiControl {
   CONTROL_BUTTON_DOWN = 0x2,
   CONTROL_BUTTON_L    = 0x4,
   CONTROL_BUTTON_R    = 0x8,
-  CONTROL_BUTTON_MASK = 0xf,
+  CONTROL_BUTTON_M    = 0x10,
 
-  CONTROL_ENCODER_L   = 0x10,
-  CONTROL_ENCODER_R   = 0x20,
+  CONTROL_ENCODER_L   = 0x20,
+  CONTROL_ENCODER_R   = 0x40,
 
+  #ifdef VOR
+  CONTROL_LAST = 6,
+  CONTROL_BUTTON_LAST = 5,
+  #else
   CONTROL_LAST = 5,
   CONTROL_BUTTON_LAST = 4,
+  #endif
 };
 
 static inline uint16_t control_mask(unsigned i) {
@@ -109,8 +115,8 @@ class Ui {
   uint32_t ticks_;
   uint32_t screensaver_timeout_;
 
-  UI::Button buttons_[4];
-  uint32_t button_press_time_[4];
+  UI::Button buttons_[CONTROL_BUTTON_LAST];
+  uint32_t button_press_time_[CONTROL_BUTTON_LAST];
   uint16_t button_state_;
   uint16_t button_ignore_mask_;
   bool screensaver_;
diff --git a/software/o_c_REV/OC_version.h b/software/o_c_REV/OC_version.h
index 80bd1c7c..f4017cf7 100644
--- a/software/o_c_REV/OC_version.h
+++ b/software/o_c_REV/OC_version.h
@@ -3,5 +3,5 @@
 //
 // GENERATED FILE, DO NOT EDIT
 //
-#define OC_VERSION "v1.3.5"
+#define OC_VERSION "v1.3.6"
 #endif
diff --git a/software/o_c_REV/VBiasManager.h b/software/o_c_REV/VBiasManager.h
new file mode 100644
index 00000000..9505f584
--- /dev/null
+++ b/software/o_c_REV/VBiasManager.h
@@ -0,0 +1,138 @@
+// Copyright (c) 2019, Jason Justian
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// This singleton class has a few jobs related to keeping track of the bias value
+// selected by the user and/or the app:
+//
+// (1) It allows advancing bias through three settings, one at a time
+// (2) It allows setting the bias directly with a state
+// (3) It shows a popup indicator for one second when the setting is advanced
+
+#ifndef VBIAS_MANAGER_H
+#define VBIAS_MANAGER_H
+
+#include "OC_options.h"
+
+#ifdef VOR 
+
+#define BIAS_EDITOR_TIMEOUT 16666
+
+class VBiasManager {
+    static VBiasManager *instance;
+    int bias_state;
+    uint32_t last_advance_tick;
+
+    VBiasManager() {
+        bias_state = 0;
+        last_advance_tick = 0;
+    }
+
+public:
+    static const int UNI = 0;
+    static const int ASYM = 1;
+    static const int BI = 2;
+
+    static VBiasManager *get() {
+        if (!instance) instance = new VBiasManager;
+        return instance;
+    }
+
+    /*
+     * Advance to the next state, when the button is pushed
+     */
+    void AdvanceBias() {
+        // Only advance the bias if it's been less than a second since the last button press.
+        // This is so that the first button press shows the popup without changing anything.
+        if (OC::CORE::ticks - last_advance_tick < BIAS_EDITOR_TIMEOUT) {
+            if (++bias_state > 2) bias_state = 0;
+            instance->ChangeBiasToState(bias_state);
+        }
+        last_advance_tick = OC::CORE::ticks;
+    }
+
+    int IsEditing() {
+        return (OC::CORE::ticks - last_advance_tick < BIAS_EDITOR_TIMEOUT);
+    }
+
+    /*
+     * Change to a specific state. This should replace a direct call to OC::DAC::set_Vbias(), because it
+     * allows VBiasManager to keep track of the current state so that the button advances the state as
+     * expected. For example:
+     *
+     * #ifdef VOR
+     *     VBiasManager *vbias_m = vbias_m->get();
+     *     vbias_m->ChangeBiasToState(VBiasManager::UNI);
+     * #endif
+     *
+     */
+    void ChangeBiasToState(int new_bias_state) {
+        int new_bias_value = OC::calibration_data.v_bias & 0xFFFF; // Bipolar = lower 2 bytes
+        if (new_bias_state == VBiasManager::UNI) new_bias_value = OC::DAC::VBiasUnipolar;
+        if (new_bias_state == VBiasManager::ASYM) new_bias_value = (OC::calibration_data.v_bias >> 16); // asym. = upper 2 bytes
+        OC::DAC::set_Vbias(new_bias_value);
+        bias_state = new_bias_state;
+    }
+
+    void SetStateForApp(int app_index) {
+        int new_state = VBiasManager::ASYM;
+        switch (app_index)
+        {
+        case 0: new_state = VBiasManager::ASYM; break;  // CopierMachine (or) ASR
+        case 1: new_state = VBiasManager::ASYM; break;  // Harrington 1200 (or) Triads
+        case 2: new_state = VBiasManager::ASYM; break;  // Automatonnetz (or) Vectors
+        case 3: new_state = VBiasManager::ASYM; break;  // Quantermain (or) 4x Quantizer
+        case 4: new_state = VBiasManager::ASYM; break;  // Meta-Q (or) 2x Quantizer
+        case 5: new_state = VBiasManager::BI; break;    // Quadraturia (or) Quadrature LFO
+        case 6: new_state = VBiasManager::BI; break;  // Low-rents (or) Lorenz
+        case 7: new_state = VBiasManager::UNI; break;   // Piqued (or) 4x EG
+        case 8: new_state = VBiasManager::ASYM; break;  // Sequins (or) 2x Sequencer
+        case 9: new_state = VBiasManager::UNI; break;   // Dialectic Ping Pong (or) Balls
+        case 10: new_state = VBiasManager::UNI; break;  // Viznutcracker sweet (or) Bytebeats
+        case 11: new_state = VBiasManager::ASYM; break; // Acid Curds (or) Chords
+        case 12: new_state = VBiasManager::UNI; break;  // References (or) Voltages
+        }
+        instance->ChangeBiasToState(new_state);
+    }
+
+    /*
+     * If the last state advance (with the button) was less than a second ago, draw the popup indicator
+     */
+    void DrawPopupPerhaps() {
+        if (OC::CORE::ticks - last_advance_tick < BIAS_EDITOR_TIMEOUT) {
+            graphics.clearRect(17, 7, 82, 43);
+            graphics.drawFrame(18, 8, 80, 42);
+
+            graphics.setPrintPos(20, 10);
+            graphics.print("VOR:");
+            graphics.setPrintPos(30, 20);
+            graphics.print(" 0V -> 10V");
+            graphics.setPrintPos(30, 30);
+            graphics.print("-3V -> 7V");
+            graphics.setPrintPos(30, 40);
+            graphics.print("-5V -> 5V");
+
+            graphics.setPrintPos(20, 20 + (bias_state * 10));
+            graphics.print("> ");
+        }
+    }
+};
+
+#endif // VBIAS_MANAGER_H
+#endif
diff --git a/software/o_c_REV/o_c_REV.ino b/software/o_c_REV/o_c_REV.ino
index 7cd3e7b2..098bc866 100644
--- a/software/o_c_REV/o_c_REV.ino
+++ b/software/o_c_REV/o_c_REV.ino
@@ -40,6 +40,7 @@
 #include "src/drivers/display.h"
 #include "src/drivers/ADC/OC_util_ADC.h"
 #include "util/util_debugpins.h"
+#include "VBiasManager.h"
 
 unsigned long LAST_REDRAW_TIME = 0;
 uint_fast8_t MENU_REDRAW = true;
@@ -166,6 +167,13 @@ void FASTRUN loop() {
           OC_DEBUG_PROFILE_SCOPE(OC::DEBUG::MENU_draw_cycles);
           OC::apps::current_app->DrawMenu();
           ++menu_redraws;
+          
+          #ifdef VOR
+            // JEJ:On app screens, show the bias popup, if necessary
+            VBiasManager *vbias_m = vbias_m->get();
+            vbias_m->DrawPopupPerhaps();
+          #endif
+          
         } else {
           OC::apps::current_app->DrawScreensaver();
         }
diff --git a/software/o_c_REV/peaks_multistage_envelope.cpp b/software/o_c_REV/peaks_multistage_envelope.cpp
index 022c9682..6d4de762 100644
--- a/software/o_c_REV/peaks_multistage_envelope.cpp
+++ b/software/o_c_REV/peaks_multistage_envelope.cpp
@@ -137,6 +137,8 @@ uint16_t MultistageEnvelope::ProcessSingleSample(uint8_t control) {
   }
   #ifdef BUCHLA_4U
     return(static_cast<uint16_t>(scaled_value_ << 1));
+  #elif defined(VOR)
+    return(static_cast<uint16_t>(scaled_value_ << 1));
   #else
     return(static_cast<uint16_t>(scaled_value_));
   #endif