diff --git a/CMakeLists.txt b/CMakeLists.txt
index aaec462..7dab9d6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@ pkg_check_modules(JACK jack>=0.118)
 SET(SOURCES
 	client.cpp
 	client.h
+	cvbase.h
 	cvin.cpp
 	cvin.h
 	cvout.cpp
diff --git a/cvbase.h b/cvbase.h
new file mode 100644
index 0000000..63dd759
--- /dev/null
+++ b/cvbase.h
@@ -0,0 +1,31 @@
+#ifndef CVBASE_H
+#define CVBASE_H
+
+#include "client.h"
+#include "mapping.h"
+
+class CVBase : protected Client
+{
+protected:
+	MappingList  m_mapping_list;
+	bool         m_ready;
+	tick_t       m_tick;
+
+	sample_t **m_buffers;
+
+	MappingList::iterator m_it_begin;
+	MappingList::iterator m_it_end;
+
+public:
+	void add_mapping(Mapping m)
+	{
+		m_mapping_list.push_back(m);
+	}
+
+	void stop()
+	{
+		close();
+	}
+};
+
+#endif // CVBASE_H
diff --git a/cvin.h b/cvin.h
index b1a0b77..013bf60 100644
--- a/cvin.h
+++ b/cvin.h
@@ -1,36 +1,18 @@
 #ifndef CVIN_H
 #define CVIN_H
 
-#include "client.h"
-#include "mapping.h"
+#include "cvbase.h"
 
-class CVIn : Client
+class CVIn : public CVBase
 {
 private:
-	MappingList  m_mapping_list;
 	jack_port_t *m_midi_out;
-	bool         m_ready;
-	tick_t       m_tick;
-
-	sample_t **m_buffers;
-
-	MappingList::iterator m_it_begin;
-	MappingList::iterator m_it_end;
 
 	void shutdown();
 	int process(jack_nframes_t nframes);
 
 public:
-	void add_mapping(Mapping m)
-	{
-		m_mapping_list.push_back(m);
-	}
-
 	void start();
-	void stop()
-	{
-		close();
-	}
 };
 
 #endif // CVIN_H
diff --git a/cvout.h b/cvout.h
index 513229b..9b41e2e 100644
--- a/cvout.h
+++ b/cvout.h
@@ -1,20 +1,14 @@
-#include "client.h"
-#include "mapping.h"
+#ifndef CVOUT_H
+#define CVOUT_H
+
+#include "cvbase.h"
 
 #define MAX_MIDI_CHANNELS 16
 
-class CVOut : Client
+class CVOut : public CVBase
 {
 private:
-	MappingList  m_mapping_list;
 	jack_port_t *m_midi_in;
-	bool         m_ready;
-	tick_t       m_tick;
-
-	sample_t **m_buffers;
-
-	MappingList::iterator m_it_begin;
-	MappingList::iterator m_it_end;
 
 	char m_nrpn_msb[MAX_MIDI_CHANNELS];
 	char m_nrpn_lsb[MAX_MIDI_CHANNELS];
@@ -24,15 +18,7 @@ private:
 	int process(jack_nframes_t nframes);
 
 public:
-	void add_mapping(Mapping m)
-	{
-		m_mapping_list.push_back(m);
-	}
-
 	void start();
-	void stop()
-	{
-		close();
-	}
 };
 
+#endif // CVOUT_H