--- mess-git22/src/emu/sound/sn76496.c	2014-07-21 06:27:27.000000000 -0300
+++ mess-new22/src/emu/sound/sn76496.c	2014-07-23 16:20:14.000000000 -0300
@@ -121,6 +121,7 @@
 #include "sn76496.h"
 
 #define MAX_OUTPUT 0x7fff
+#define PSG_CUTOFF 0x6  /* Value below which PSG does not output */
 
 
 sn76496_base_device::sn76496_base_device(const machine_config &mconfig, device_type type,  const char *name,
@@ -326,7 +327,14 @@ void sn76496_base_device::sound_stream_u
 				m_count[i]--;
 				if (m_count[i] <= 0)
 				{
-					m_output[i] ^= 1;
+					if (m_register[2*i] > PSG_CUTOFF)
+					{
+						m_output[i] ^= 1;
+					}
+					else
+					{
+						m_output[i] = 1;
+					}
 					m_count[i] = m_period[i];
 				}
 			}