diff --git a/src/mame/audio/nl_barrier.cpp b/src/mame/audio/nl_barrier.cpp
index 6fba85cb579..a1bae48963d 100644
--- a/src/mame/audio/nl_barrier.cpp
+++ b/src/mame/audio/nl_barrier.cpp
@@ -182,7 +182,7 @@ NETLIST_START(barrier)
 	NET_C(NOISE_CLOCK.GND, GND)
 	NET_C(NOISE_CLOCK.VCC, I_V5)
 
-	SYS_NOISE_MT_U(NOISE, 3)
+	SYS_NOISE_MT_U(NOISE, 0.0001)
 	NET_C(NOISE.I, NOISE_CLOCK.Q)
 	NET_C(NOISE.1, GND)
 	NET_C(NOISE.2, C1.1)
diff --git a/src/mame/audio/nl_spacewar.cpp b/src/mame/audio/nl_spacewar.cpp
index 53bae689243..b733a1b0846 100644
--- a/src/mame/audio/nl_spacewar.cpp
+++ b/src/mame/audio/nl_spacewar.cpp
@@ -193,7 +193,7 @@ NETLIST_START(spacewar)
 	NET_C(NOISE_CLOCK.GND, GND)
 	NET_C(NOISE_CLOCK.VCC, I_V5)
 
-	SYS_NOISE_MT_U(NOISE, 3)
+	SYS_NOISE_MT_N(NOISE, 0.0001)
 	NET_C(NOISE.I, NOISE_CLOCK.Q)
 	NET_C(NOISE.1, GND)
 	NET_C(NOISE.2, C1.1)