diff --git a/SimPEG/MT/SrcMT.py b/SimPEG/MT/SrcMT.py
index 9679217d..148ecab4 100644
--- a/SimPEG/MT/SrcMT.py
+++ b/SimPEG/MT/SrcMT.py
@@ -1,11 +1,10 @@
-from SimPEG import Survey, Utils, Problem, Maps, np, sp, mkvc
+from SimPEG import Utils, Problem, Maps, np, sp, mkvc
 from SimPEG.EM.FDEM.SrcFDEM import BaseSrc as FDEMBaseSrc
 from SimPEG.EM.Utils import omega
 from scipy.constants import mu_0
 from numpy.lib import recfunctions as recFunc
 from Sources import homo1DModelSource
 from Utils import rec2ndarr
-from SurveyMT import Rx
 import sys
 
 #################
@@ -22,7 +21,6 @@ class BaseMTSrc(FDEMBaseSrc):
     '''
 
     freq = None #: Frequency (float)
-    rxPair = Rx
 
 
     def __init__(self, rxList, freq):
diff --git a/SimPEG/MT/SurveyMT.py b/SimPEG/MT/SurveyMT.py
index ed041a12..463d8211 100644
--- a/SimPEG/MT/SurveyMT.py
+++ b/SimPEG/MT/SurveyMT.py
@@ -230,6 +230,9 @@ class Rx(SimPEGsurvey.BaseRx):
 
                 # Calculate the complex derivative
                 PDeriv_complex = Hd * (ZijN_uV - Zij * Hd_uV )
+            elif self.projTyep is 'T3D':
+                raise NotImplementedError('Has not been implement for 3D tipper tensor')
+
             # Extract the real number for the real/imag components.
             Pv = np.array(getattr(PDeriv_complex, real_or_imag))
         elif adjoint: