diff --git a/Lib/aifc.py b/Lib/aifc.py
index 8e4f864..f9db3f4 100644
--- a/Lib/aifc.py
+++ b/Lib/aifc.py
@@ -732,6 +732,8 @@
         if self._comp:
             self._comp.CloseCompressor()
             self._comp = None
+        # Prevent ref cycles
+        self._convert = None
         self._file.flush()
         self._file = None