diff --git a/SimPEG/EM/FDEM/SrcFDEM.py b/SimPEG/EM/FDEM/SrcFDEM.py
index 8c78b116..54214e4f 100644
--- a/SimPEG/EM/FDEM/SrcFDEM.py
+++ b/SimPEG/EM/FDEM/SrcFDEM.py
@@ -626,7 +626,7 @@ class PrimSecSigma(BaseSrc):
 
     def s_eDeriv(self, prob, v, adjoint=False):
         if adjoint:
-            return prob.MeSigmaDeriv(self.ePrimary).T * v
-        return prob.MeSigmaDeriv(self.ePrimary).T * v
+            return prob.MeSigmaDeriv(self.ePrimary(prob)).T * v
+        return prob.MeSigmaDeriv(self.ePrimary(prob)).T * v