diff --git a/src/devices/bus/cbus/pc9801_86.cpp b/src/devices/bus/cbus/pc9801_86.cpp
index fbea8ebee05..094a50be752 100644
--- a/src/devices/bus/cbus/pc9801_86.cpp
+++ b/src/devices/bus/cbus/pc9801_86.cpp
@@ -56,6 +56,7 @@ MACHINE_CONFIG_START(pc9801_86_device::device_add_mconfig)
 	MCFG_SPEAKER_STANDARD_STEREO("lspeaker", "rspeaker")
 	MCFG_SOUND_ADD("opna", YM2608, 7.987_MHz_XTAL)
 	MCFG_YM2608_IRQ_HANDLER(WRITELINE(pc9801_86_device, sound_irq))
+	MCFG_AY8910_OUTPUT_TYPE(0)
 	MCFG_AY8910_PORT_A_READ_CB(READ8(pc9801_86_device, opn_porta_r))
 	//MCFG_AY8910_PORT_B_READ_CB(READ8(pc9801_state, opn_portb_r))
 	//MCFG_AY8910_PORT_A_WRITE_CB(WRITE8(pc9801_state, opn_porta_w))