diff --git a/src/mame/audio/mw8080bw.c b/src/mame/audio/mw8080bw.c
index 46054e2473e..7ce4a766b1e 100644
--- a/src/mame/audio/mw8080bw.c
+++ b/src/mame/audio/mw8080bw.c
@@ -567,20 +567,22 @@ MACHINE_DRIVER_END
 
 void maze_write_discrete(running_machine *machine, UINT8 maze_tone_timing_state)
 {
+	const address_space *space = cpu_get_address_space(machine->cpu[0], ADDRESS_SPACE_PROGRAM);
+
 	/* controls need to be active low */
 	int controls = ~input_port_read(machine, "IN0") & 0xff;
 
-	discrete_sound_w(machine, MAZE_TONE_TIMING, maze_tone_timing_state);
-	discrete_sound_w(machine, MAZE_P1_DATA, controls & 0x0f);
-	discrete_sound_w(machine, MAZE_P2_DATA, (controls >> 4) & 0x0f);
-	discrete_sound_w(machine, MAZE_JOYSTICK_IN_USE, controls != 0xff);
+	discrete_sound_w(space, MAZE_TONE_TIMING, maze_tone_timing_state);
+	discrete_sound_w(space, MAZE_P1_DATA, controls & 0x0f);
+	discrete_sound_w(space, MAZE_P2_DATA, (controls >> 4) & 0x0f);
+	discrete_sound_w(space, MAZE_JOYSTICK_IN_USE, controls != 0xff);
 
 	/* The coin line is connected directly to the discrete circuit. */
 	/* We can't really do that, so updating it with the tone timing is close enough. */
 	/* A better option might be to update it at vblank or set a timer to do it. */
 	/* The only noticeable difference doing it here, is that the controls don't */
 	/* imediately start making tones if pressed right after the coin is inserted. */
-	discrete_sound_w(machine, MAZE_COIN, (~input_port_read(machine, "IN1") >> 3) & 0x01);
+	discrete_sound_w(space, MAZE_COIN, (~input_port_read(machine, "IN1") >> 3) & 0x01);
 }