diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py b/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
index 140638d3c..b406da0c7 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/zipformer.py
@@ -1306,7 +1306,7 @@ class AttentionSqueeze(nn.Module):
             max_factor=0.02,
             min_prob=0.1,
         )
-        self.bottleneck_activation = DoubleSwish()   # in bottleneck
+        self.bottleneck_activation = nn.Tanh()   # in bottleneck
         self.activation = Identity() # for diagnostics
 
         # the next two balancers are only to stop parameter-magnitude 'drift': we have