diff --git a/src/kyupy/wave_sim.py b/src/kyupy/wave_sim.py
index 7bee0a2..0ca6fd1 100644
--- a/src/kyupy/wave_sim.py
+++ b/src/kyupy/wave_sim.py
@@ -179,7 +179,7 @@ def _wave_eval(op, cbuf, c_locs, c_caps, ebuf, sim, delays, simctl_int, seed, de
     if (delta):
         if input_epoch == 0 and output_epoch == 0: return 0, 0
 
-    out_changed = output_epoch
+    #out_changed = output_epoch
 
     if len(delays) > 1:
         if simctl_int[1] == 0:
@@ -254,8 +254,8 @@ def _wave_eval(op, cbuf, c_locs, c_caps, ebuf, sim, delays, simctl_int, seed, de
                 or (current_t - previous_t) > thresh  # -OR- the generated hazard is wider than pulse threshold.
                 ):
                 if z_cur < (z_cap - 1):  # enough space in z_mem?
-                    if delta and (cbuf[z_mem + z_cur, sim] != current_t):
-                        out_changed = 1
+                    #if delta and (cbuf[z_mem + z_cur, sim] != current_t):
+                    #    out_changed = 1
                     cbuf[z_mem + z_cur, sim] = current_t
                     previous_t = current_t
                     z_cur += 1
@@ -276,8 +276,8 @@ def _wave_eval(op, cbuf, c_locs, c_caps, ebuf, sim, delays, simctl_int, seed, de
 
         current_t = min(a, b, c, d)
 
-    if delta and (cbuf[z_mem + z_cur, sim] != TMAX):
-        out_changed = 1
+    #if delta and (cbuf[z_mem + z_cur, sim] != TMAX):
+    #    out_changed = 1
 
     # generate or propagate overflow flag
     cbuf[z_mem + z_cur, sim] = TMAX_OVL if overflows > 0 else max(a, b, c, d)
@@ -291,7 +291,7 @@ def _wave_eval(op, cbuf, c_locs, c_caps, ebuf, sim, delays, simctl_int, seed, de
 
     ebuf[z_idx, sim, 0] = e
 
-    ebuf[z_idx, sim, 1] = input_epoch & out_changed
+    ebuf[z_idx, sim, 1] = input_epoch #& out_changed
 
     return nrise, nfall