diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/train.py b/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
index 79860ffbc..af7503ada 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
@@ -127,7 +127,7 @@ def add_model_arguments(parser: argparse.ArgumentParser):
     parser.add_argument(
         "--num-heads",
         type=str,
-        default="8",
+        default="8,8,8,16,8,8",
         help="Number of attention heads in the zipformer encoder layers: a single int or comma-separated list.",
     )