diff --git a/peaks/drums/high_hat.h b/peaks/drums/high_hat.h
index bc6ab9152..526eb976b 100644
--- a/peaks/drums/high_hat.h
+++ b/peaks/drums/high_hat.h
@@ -52,7 +52,7 @@ class HighHat {
   Svf vca_coloration_;
   Excitation vca_envelope_;
   
-  uint32_t phase_[6];
+  uint32_t phase_[6] = {};
 
   DISALLOW_COPY_AND_ASSIGN(HighHat);
 };
diff --git a/peaks/modulations/mini_sequencer.h b/peaks/modulations/mini_sequencer.h
index 6ee3fb0c4..e5f32e551 100644
--- a/peaks/modulations/mini_sequencer.h
+++ b/peaks/modulations/mini_sequencer.h
@@ -99,7 +99,7 @@ class MiniSequencer {
  private:
   uint8_t num_steps_;
   uint8_t step_;
-  int16_t steps_[kMaxNumSteps];
+  int16_t steps_[kMaxNumSteps] = {};
 
   bool reset_at_next_clock_;
 
diff --git a/peaks/processors.h b/peaks/processors.h
index 09a11ab25..9be88aa69 100755
--- a/peaks/processors.h
+++ b/peaks/processors.h
@@ -149,7 +149,7 @@ class Processors {
   
   ControlMode control_mode_;
   ProcessorFunction function_;
-  uint16_t parameter_[4];
+  uint16_t parameter_[4] = {};
   
   ProcessorCallbacks callbacks_;
   static const ProcessorCallbacks callbacks_table_[PROCESSOR_FUNCTION_LAST];
diff --git a/peaks/pulse_processor/pulse_randomizer.h b/peaks/pulse_processor/pulse_randomizer.h
index 2752664b6..39d49f212 100644
--- a/peaks/pulse_processor/pulse_randomizer.h
+++ b/peaks/pulse_processor/pulse_randomizer.h
@@ -91,7 +91,7 @@ class PulseRandomizer {
   uint16_t num_pulses_;
   uint16_t retrig_counter_;
   
-  uint16_t delay_counter_[kTriggerPulseBufferSize];
+  uint16_t delay_counter_[kTriggerPulseBufferSize] = {};
 
   DISALLOW_COPY_AND_ASSIGN(PulseRandomizer);
 };
diff --git a/peaks/pulse_processor/pulse_shaper.h b/peaks/pulse_processor/pulse_shaper.h
index 83f193ee1..02a1c6078 100644
--- a/peaks/pulse_processor/pulse_shaper.h
+++ b/peaks/pulse_processor/pulse_shaper.h
@@ -96,7 +96,7 @@ class PulseShaper {
   uint16_t previous_num_pulses_;
   uint16_t retrig_counter_;
   
-  Pulse pulse_buffer_[kPulseBufferSize];
+  Pulse pulse_buffer_[kPulseBufferSize] = {};
 
   DISALLOW_COPY_AND_ASSIGN(PulseShaper);
 };
diff --git a/peaks/ui.h b/peaks/ui.h
index 2c507207d..ac6fca027 100755
--- a/peaks/ui.h
+++ b/peaks/ui.h
@@ -117,11 +117,11 @@ class Ui {
   void SetFunction(uint8_t index, Function f);
   void SaveState();
 
-  int32_t adc_lp_[kNumAdcChannels];
-  int32_t adc_value_[kNumAdcChannels];
-  int32_t adc_threshold_[kNumAdcChannels];
-  uint32_t press_time_[kNumSwitches];
-  bool panel_gate_control_[2];
+  int32_t adc_lp_[kNumAdcChannels] = {};
+  int32_t adc_value_[kNumAdcChannels] = {};
+  int32_t adc_threshold_[kNumAdcChannels] = {};
+  uint32_t press_time_[kNumSwitches] = {};
+  bool panel_gate_control_[2] = {};
   static const ProcessorFunction function_table_[FUNCTION_LAST][2];
   
   stmlib::EventQueue<32> queue_;
@@ -131,19 +131,19 @@ class Ui {
   Adc adc_;
   
   EditMode edit_mode_;
-  Function function_[2];
+  Function function_[2] = {};
   Settings settings_;
   uint16_t version_token_;
   
-  int16_t brightness_[2];
+  int16_t brightness_[2] = {};
   
   uint8_t panel_gate_state_;
   
   uint8_t double_press_counter_;
-  uint8_t pot_value_[8];
+  uint8_t pot_value_[8] = {};
   
   bool snap_mode_;
-  bool snapped_[kNumAdcChannels];
+  bool snapped_[kNumAdcChannels] = {};
   
   CalibrationData* calibration_data_;
   bool calibrating_;