diff --git a/nifty5/library/correlated_fields.py b/nifty5/library/correlated_fields.py
index bb5e58fa91170c3f37ec481f29830e764716627c..edd4ea05aec97c7491d14dca3a44913d5c866556 100644
--- a/nifty5/library/correlated_fields.py
+++ b/nifty5/library/correlated_fields.py
@@ -232,9 +232,13 @@ class _Amplitude(Operator):
         op = Adder(vol0) @ (sig_fluc*op)
 
         self.apply = op.apply
-        self.fluctuation_amplitude = fluctuations
+        self._fluc = fluctuations
         self._domain, self._target = op.domain, op.target
 
+    @property
+    def fluctuation_amplitude(self):
+        return self._fluc
+
 
 class CorrelatedFieldMaker:
     def __init__(self):