diff --git a/src/devices/sound/ics2115.cpp b/src/devices/sound/ics2115.cpp
index a84a5c1208e..56c0cf607c4 100644
--- a/src/devices/sound/ics2115.cpp
+++ b/src/devices/sound/ics2115.cpp
@@ -1105,22 +1105,14 @@ TIMER_CALLBACK_MEMBER( ics2115_device::timer_cb_1 )
 
 void ics2115_device::recalc_timer(int timer)
 {
-	//Old regression-based formula (minus constant)
-	//u64 period = m_timer[timer].preset * (m_timer[timer].scale << 16) / 60;
-
-	//New formula based on O.Galibert's reverse engineering of ICS2115 card firmware
-	// TODO : Related to input clock?
 	u64 period  = ((m_timer[timer].scale & 0x1f) + 1) * (m_timer[timer].preset + 1);
-	period = (period << (4 + (m_timer[timer].scale >> 5)))*78125/2646;
+	period = period << (4 + (m_timer[timer].scale >> 5));
 
 	if (m_timer[timer].period != period)
 	{
-		logerror("Timer %d period %dns (%dHz)\n", timer, period, 1e9/period);
+		attotime tp = attotime::from_ticks(period, clock());
+		logerror("Timer %d period %dns (%dHz)\n", timer, int(tp.as_double()*1e9), int(1/tp.as_double()));
 		m_timer[timer].period = period;
-		// Adjust the timer lengths
-		if (period) // Reset the length
-			m_timer[timer].timer->adjust(attotime::from_nsec(period), 0, attotime::from_nsec(period));
-		else // Kill the timer if length == 0
-			m_timer[timer].timer->adjust(attotime::never);
+		m_timer[timer].timer->adjust(tp, 0, tp);
 	}
 }