diff --git a/simpegEM/FDEM/SurveyFDEM.py b/simpegEM/FDEM/SurveyFDEM.py
index 67db6674..dce06ba5 100644
--- a/simpegEM/FDEM/SurveyFDEM.py
+++ b/simpegEM/FDEM/SurveyFDEM.py
@@ -1,4 +1,4 @@
-from SimPEG import Survey, Utils, np, sp
+from SimPEG import Survey, Problem, Utils, np, sp
 
 class RxFDEM(Survey.BaseRx):
 
@@ -79,7 +79,7 @@ class TxFDEM(Survey.BaseTx):
 
 
 
-class FieldsFDEM(Survey.Fields):
+class FieldsFDEM(Problem.Fields):
     """Fancy Field Storage for a FDEM survey."""
     knownFields = {'b': 'F', 'e': 'E'}
     dtype = complex
diff --git a/simpegEM/TDEM/BaseTDEM.py b/simpegEM/TDEM/BaseTDEM.py
index 8b876f45..d12e776e 100644
--- a/simpegEM/TDEM/BaseTDEM.py
+++ b/simpegEM/TDEM/BaseTDEM.py
@@ -1,7 +1,6 @@
-from SimPEG import Solver
+from SimPEG import Solver, Problem
 from SimPEG.Problem import BaseTimeProblem
 from simpegEM.Utils import Sources
-from SurveyTDEM import FieldsTDEM, SurveyTDEM
 from scipy.constants import mu_0
 from SimPEG.Utils import sdiag, mkvc
 from SimPEG import Utils, Mesh
@@ -9,12 +8,33 @@ from simpegEM.Base import BaseEMProblem
 import numpy as np
 
 
+class FieldsTDEM(Problem.TimeFields):
+    """Fancy Field Storage for a TDEM survey."""
+    knownFields = {'b': 'F', 'e': 'E'}
+
+    def tovec(self):
+        nTx, nF, nE = self.survey.nTx, self.mesh.nF, self.mesh.nE
+        u = np.empty(0 if nTx == 1 else (0, nTx))
+
+        for i in range(self.survey.prob.nT):
+            if 'b' in self:
+                b = self[:,'b',i+1]
+            else:
+                b = np.zeros(nF if nTx == 1 else (nF, nTx))
+
+            if 'e' in self:
+                e = self[:,'e',i+1]
+            else:
+                e = np.zeros(nE if nTx == 1 else (nE, nTx))
+            u = np.concatenate((u, b, e))
+        return Utils.mkvc(u)
+
+
 class BaseTDEMProblem(BaseTimeProblem, BaseEMProblem):
     """docstring for ProblemTDEM1D"""
     def __init__(self, mesh, mapping=None, **kwargs):
         BaseTimeProblem.__init__(self, mesh, mapping=mapping, **kwargs)
 
-    surveyPair = SurveyTDEM
     _FieldsForward_pair = FieldsTDEM  #: used for the forward calculation only
 
     def fields(self, m):
diff --git a/simpegEM/TDEM/SurveyTDEM.py b/simpegEM/TDEM/SurveyTDEM.py
index c9a67856..b4cc1b5d 100644
--- a/simpegEM/TDEM/SurveyTDEM.py
+++ b/simpegEM/TDEM/SurveyTDEM.py
@@ -1,6 +1,7 @@
 from SimPEG import Utils, Survey, np
 from SimPEG.Survey import BaseSurvey
 from simpegEM.Utils import Sources
+from BaseTDEM import FieldsTDEM
 
 
 class RxTDEM(Survey.BaseTimeRx):
@@ -64,27 +65,6 @@ class RxTDEM(Survey.BaseTimeRx):
             return P.T * v[tx, self]
 
 
-class FieldsTDEM(Survey.TimeFields):
-    """Fancy Field Storage for a TDEM survey."""
-    knownFields = {'b': 'F', 'e': 'E'}
-
-    def tovec(self):
-        nTx, nF, nE = self.survey.nTx, self.mesh.nF, self.mesh.nE
-        u = np.empty(0 if nTx == 1 else (0, nTx))
-
-        for i in range(self.survey.prob.nT):
-            if 'b' in self:
-                b = self[:,'b',i+1]
-            else:
-                b = np.zeros(nF if nTx == 1 else (nF, nTx))
-
-            if 'e' in self:
-                e = self[:,'e',i+1]
-            else:
-                e = np.zeros(nE if nTx == 1 else (nE, nTx))
-            u = np.concatenate((u, b, e))
-        return Utils.mkvc(u)
-
 class TxTDEM(Survey.BaseTx):
     rxPair = RxTDEM
     knownTxTypes = ['VMD_MVP']
diff --git a/simpegEM/TDEM/TDEM_b.py b/simpegEM/TDEM/TDEM_b.py
index 90e91ea3..a9acc181 100644
--- a/simpegEM/TDEM/TDEM_b.py
+++ b/simpegEM/TDEM/TDEM_b.py
@@ -1,7 +1,7 @@
-from BaseTDEM import BaseTDEMProblem
+from BaseTDEM import BaseTDEMProblem, FieldsTDEM
 from SimPEG.Utils import mkvc
 import numpy as np
-from SurveyTDEM import SurveyTDEM, FieldsTDEM
+from SurveyTDEM import SurveyTDEM
 
 
 class FieldsTDEM_e_from_b(FieldsTDEM):
diff --git a/simpegEM/TDEM/__init__.py b/simpegEM/TDEM/__init__.py
index fed1a2dc..15ff3f43 100644
--- a/simpegEM/TDEM/__init__.py
+++ b/simpegEM/TDEM/__init__.py
@@ -1,3 +1,3 @@
-from SurveyTDEM import SurveyTDEM, FieldsTDEM, RxTDEM, TxTDEM
-from BaseTDEM import BaseTDEMProblem
+from SurveyTDEM import SurveyTDEM, RxTDEM, TxTDEM
+from BaseTDEM import BaseTDEMProblem, FieldsTDEM
 from TDEM_b import ProblemTDEM_b