diff --git a/SimPEG/EM/TDEM/SrcTDEM.py b/SimPEG/EM/TDEM/SrcTDEM.py
new file mode 100644
index 00000000..ff4f9c66
--- /dev/null
+++ b/SimPEG/EM/TDEM/SrcTDEM.py
@@ -0,0 +1,204 @@
+import SimPEG
+from SimPEG import np, Utils
+from SimPEG.Utils import Zero, Identity
+from scipy.constants import mu_0
+from SimPEG.EM.Utils import *
+
+####################################################
+# Sources
+####################################################
+
+class BaseWaveform(object):
+
+    def __init__(self, offTime=0., hasInitialFields=False):
+        self.offTime = offTime
+        self.hasInitialFields = hasInitialFields
+
+    def _assertMatchesPair(self, pair):
+        assert (isinstance(self, pair)
+            ), "Waveform object must be an instance of a %s BaseWaveform class."%(pair.__name__)
+
+    def eval(self, time):
+        raise NotImplementedError
+
+    def evalDeriv(self, time):
+        raise NotImplementedError # needed for E-formulation
+
+
+class StepOffWaveform(BaseWaveform):
+
+    def __init__(self, offTime=0.):
+        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
+
+    def eval(self, time):
+        return 0.
+
+
+class RawWaveform(BaseWaveform):
+
+    def __init__(self, offTime=0.):
+        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
+
+    def eval(self, time):
+        raise NotImplementedError('RawWaveform has not been implemented, you should write it!')
+
+
+class TriangularWaveform(BaseWaveform):
+
+    def __init__(self, offTime=0.):
+        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
+
+    def eval(self, time):
+        raise NotImplementedError('TriangularWaveform has not been implemented, you should write it!')
+
+
+
+class BaseSrc(SimPEG.Survey.BaseSrc):
+
+    # rxPair = Rx
+    integrate = True
+    waveformPair = BaseWaveform
+
+    @property
+    def waveform(self):
+        "A waveform instance is not None"
+        return getattr(self, '_waveform', None)
+    @waveform.setter
+    def waveform(self, val):
+        if self.waveform is None:
+            val._assertMatchesPair(self.waveformPair)
+            self._mapping = val
+        else:
+            self._mapping = self.PropMap(val)
+
+
+    def __init__(self, rxList, waveform = StepOffWaveform(), **kwargs):
+        self.waveform = waveform
+        SimPEG.Survey.BaseSrc.__init__(self, rxList, **kwargs)
+
+
+    def bInitial(self, prob):
+        return Zero()
+
+    def bInitialDeriv(self, prob, v=None, adjoint=False):
+        return Zero()
+
+    def eInitial(self, prob):
+        return Zero()
+
+    def eInitialDeriv(self, prob, v=None, adjoint=False):
+        return Zero()
+
+    def eval(self, prob, time):
+        S_m = self.S_m(prob, time)
+        S_e = self.S_e(prob, time)
+        return S_m, S_e
+
+    def evalDeriv(self, prob, time, v=None, adjoint=False):
+        if v is not None:
+            return self.S_mDeriv(prob, time, v, adjoint), self.S_eDeriv(prob, time, v, adjoint)
+        else:
+            return lambda v: self.S_mDeriv(prob, time, v, adjoint), lambda v: self.S_eDeriv(prob, time, v, adjoint)
+
+    def S_m(self, prob, time):
+        return Zero()
+
+    def S_e(self, prob, time):
+        return Zero()
+
+    def S_mDeriv(self, prob, time, v=None, adjoint=False):
+        return Zero()
+
+    def S_eDeriv(self, prob, time, v=None, adjoint=False):
+        return Zero()
+
+
+class MagDipole(BaseSrc):
+
+    waveform = None
+    loc = None
+    orientation = 'Z'
+    moment = 1.
+    mu = mu_0
+
+    def __init__(self, rxList, **kwargs):
+        assert self.orientation in ['X','Y','Z'], "Orientation (right now) doesn't actually do anything! The methods in SrcUtils should take care of this..."
+        self.integrate = False
+        BaseSrc.__init__(self, rxList, **kwargs)
+
+    def _bfromVectorPotential(self, prob):
+        if prob._eqLocs is 'FE':
+            gridX = prob.mesh.gridEx
+            gridY = prob.mesh.gridEy
+            gridZ = prob.mesh.gridEz
+            C = prob.mesh.edgeCurl
+
+        elif prob._eqLocs is 'EF':
+            gridX = prob.mesh.gridFx
+            gridY = prob.mesh.gridFy
+            gridZ = prob.mesh.gridFz
+            C = prob.mesh.edgeCurl.T
+
+
+        if prob.mesh._meshType is 'CYL':
+            if not prob.mesh.isSymmetric:
+                raise NotImplementedError('Non-symmetric cyl mesh not implemented yet!')
+            a = MagneticDipoleVectorPotential(self.loc, gridY, 'y', mu=self.mu, moment=self.moment)
+
+        else:
+            srcfct = MagneticDipoleVectorPotential
+            ax = srcfct(self.loc, gridX, 'x', mu=self.mu, moment=self.moment)
+            ay = srcfct(self.loc, gridY, 'y', mu=self.mu, moment=self.moment)
+            az = srcfct(self.loc, gridZ, 'z', mu=self.mu, moment=self.moment)
+            a = np.concatenate((ax, ay, az))
+
+        return C*a
+
+
+    def bInitial(self, prob):
+
+        if self.waveform.hasInitialFields is False:
+            return Zero()
+
+        return self._bfromVectorPotential(prob)
+
+    def eInitial(self, prob):
+
+        if self.waveform.hasInitialFields is False:
+            return Zero()
+
+        b = self.bInitial(prob)
+        MeSigmaI = prob.MeSigmaI
+        MfMui = prob.MfMui
+        C = prob.mesh.edgeCurl
+
+        return MeSigmaI * (C.T * (MfMui * b))
+
+    def eInitialDeriv(self, prob, v=None, adjoint=False):
+
+        if self.waveform.hasInitialFields is False:
+            return Zero()
+
+        b = self.bInitial(prob)
+        MeSigmaIDeriv = prob.MeSigmaIDeriv
+        MfMui = prob.MfMui
+        C = prob.mesh.edgeCurl
+        S_e = self.S_e(prob, prob.t0)
+
+        # S_e doesn't depend on the model
+
+        if adjoint:
+            return MeSigmaIDeriv( -S_e + C.T * ( MfMui * b ) ).T * v
+
+        return MeSigmaIDeriv( -S_e + C.T * ( MfMui * b ) ) * v
+
+
+    def S_m(self, prob, time):
+        if self.waveform.hasInitialFields is False:
+            raise NotImplementedError
+        return Zero()
+
+    def S_e(self, prob, time):
+        if self.waveform.hasInitialFields is False:
+            raise NotImplementedError
+        return Zero()
diff --git a/SimPEG/EM/TDEM/SurveyTDEM.py b/SimPEG/EM/TDEM/SurveyTDEM.py
index eb534978..6acf3c04 100644
--- a/SimPEG/EM/TDEM/SurveyTDEM.py
+++ b/SimPEG/EM/TDEM/SurveyTDEM.py
@@ -3,6 +3,8 @@ from SimPEG import np, Utils
 from SimPEG.Utils import Zero, Identity
 from scipy.constants import mu_0
 from SimPEG.EM.Utils import *
+import SrcTDEM as Src
+
 
 ####################################################
 # Receivers
@@ -70,204 +72,6 @@ class Rx(SimPEG.Survey.BaseTimeRx):
             # newshape = (len(dP_dF_T)/timeMesh.nN, timeMesh.nN )
             return P.T * v #np.reshape(dP_dF_T, newshape, order='F')
 
-####################################################
-# Sources
-####################################################
-
-class BaseWaveform(object):
-
-    def __init__(self, offTime=0., hasInitialFields=False):
-        self.offTime = offTime
-        self.hasInitialFields = hasInitialFields
-
-    def _assertMatchesPair(self, pair):
-        assert (isinstance(self, pair)
-            ), "Waveform object must be an instance of a %s BaseWaveform class."%(pair.__name__)
-
-    def eval(self, time):
-        raise NotImplementedError
-
-    def evalDeriv(self, time):
-        raise NotImplementedError # needed for E-formulation
-
-
-class StepOffWaveform(BaseWaveform):
-
-    def __init__(self, offTime=0.):
-        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
-
-    def eval(self, time):
-        return 0.
-
-
-class RawWaveform(BaseWaveform):
-
-    def __init__(self, offTime=0.):
-        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
-
-    def eval(self, time):
-        raise NotImplementedError('RawWaveform has not been implemented, you should write it!')
-
-
-class TriangularWaveform(BaseWaveform):
-
-    def __init__(self, offTime=0.):
-        BaseWaveform.__init__(self, offTime, hasInitialFields=True)
-
-    def eval(self, time):
-        raise NotImplementedError('TriangularWaveform has not been implemented, you should write it!')
-
-
-
-class BaseSrc(SimPEG.Survey.BaseSrc):
-
-    rxPair = Rx
-    integrate = True
-    waveformPair = BaseWaveform
-
-    @property
-    def waveform(self):
-        "A waveform instance is not None"
-        return getattr(self, '_waveform', None)
-    @waveform.setter
-    def waveform(self, val):
-        if self.waveform is None:
-            val._assertMatchesPair(self.waveformPair)
-            self._mapping = val
-        else:
-            self._mapping = self.PropMap(val)
-
-
-    def __init__(self, rxList, waveform = StepOffWaveform(), **kwargs):
-        self.waveform = waveform
-        SimPEG.Survey.BaseSrc.__init__(self, rxList, **kwargs)
-
-
-    def bInitial(self, prob):
-        return Zero()
-
-    def bInitialDeriv(self, prob, v=None, adjoint=False):
-        return Zero()
-
-    def eInitial(self, prob):
-        return Zero()
-
-    def eInitialDeriv(self, prob, v=None, adjoint=False):
-        return Zero()
-
-    def eval(self, prob, time):
-        S_m = self.S_m(prob, time)
-        S_e = self.S_e(prob, time)
-        return S_m, S_e
-
-    def evalDeriv(self, prob, time, v=None, adjoint=False):
-        if v is not None:
-            return self.S_mDeriv(prob, time, v, adjoint), self.S_eDeriv(prob, time, v, adjoint)
-        else:
-            return lambda v: self.S_mDeriv(prob, time, v, adjoint), lambda v: self.S_eDeriv(prob, time, v, adjoint)
-
-    def S_m(self, prob, time):
-        return Zero()
-
-    def S_e(self, prob, time):
-        return Zero()
-
-    def S_mDeriv(self, prob, time, v=None, adjoint=False):
-        return Zero()
-
-    def S_eDeriv(self, prob, time, v=None, adjoint=False):
-        return Zero()
-
-
-class MagDipole(BaseSrc):
-
-    waveform = None
-    loc = None
-    orientation = 'Z'
-    moment = 1.
-    mu = mu_0
-
-    def __init__(self, rxList, **kwargs):
-        assert self.orientation in ['X','Y','Z'], "Orientation (right now) doesn't actually do anything! The methods in SrcUtils should take care of this..."
-        self.integrate = False
-        BaseSrc.__init__(self, rxList, **kwargs)
-
-    def _bfromVectorPotential(self, prob):
-        if prob._eqLocs is 'FE':
-            gridX = prob.mesh.gridEx
-            gridY = prob.mesh.gridEy
-            gridZ = prob.mesh.gridEz
-            C = prob.mesh.edgeCurl
-
-        elif prob._eqLocs is 'EF':
-            gridX = prob.mesh.gridFx
-            gridY = prob.mesh.gridFy
-            gridZ = prob.mesh.gridFz
-            C = prob.mesh.edgeCurl.T
-
-
-        if prob.mesh._meshType is 'CYL':
-            if not prob.mesh.isSymmetric:
-                raise NotImplementedError('Non-symmetric cyl mesh not implemented yet!')
-            a = MagneticDipoleVectorPotential(self.loc, gridY, 'y', mu=self.mu, moment=self.moment)
-
-        else:
-            srcfct = MagneticDipoleVectorPotential
-            ax = srcfct(self.loc, gridX, 'x', mu=self.mu, moment=self.moment)
-            ay = srcfct(self.loc, gridY, 'y', mu=self.mu, moment=self.moment)
-            az = srcfct(self.loc, gridZ, 'z', mu=self.mu, moment=self.moment)
-            a = np.concatenate((ax, ay, az))
-
-        return C*a
-
-
-    def bInitial(self, prob):
-
-        if self.waveform.hasInitialFields is False:
-            return Zero()
-
-        return self._bfromVectorPotential(prob)
-
-    def eInitial(self, prob):
-
-        if self.waveform.hasInitialFields is False:
-            return Zero()
-
-        b = self.bInitial(prob)
-        MeSigmaI = prob.MeSigmaI
-        MfMui = prob.MfMui
-        C = prob.mesh.edgeCurl
-
-        return MeSigmaI * (C.T * (MfMui * b))
-
-    def eInitialDeriv(self, prob, v=None, adjoint=False):
-
-        if self.waveform.hasInitialFields is False:
-            return Zero()
-
-        b = self.bInitial(prob)
-        MeSigmaIDeriv = prob.MeSigmaIDeriv
-        MfMui = prob.MfMui
-        C = prob.mesh.edgeCurl
-        S_e = self.S_e(prob, prob.t0)
-
-        # S_e doesn't depend on the model
-
-        if adjoint:
-            return MeSigmaIDeriv( -S_e + C.T * ( MfMui * b ) ).T * v
-
-        return MeSigmaIDeriv( -S_e + C.T * ( MfMui * b ) ) * v
-
-
-    def S_m(self, prob, time):
-        if self.waveform.hasInitialFields is False:
-            raise NotImplementedError
-        return Zero()
-
-    def S_e(self, prob, time):
-        if self.waveform.hasInitialFields is False:
-            raise NotImplementedError
-        return Zero()
 
 ####################################################
 # Survey
@@ -278,7 +82,7 @@ class Survey(SimPEG.Survey.BaseSurvey):
     Time domain electromagnetic survey
     """
 
-    srcPair = BaseSrc
+    srcPair = Src.BaseSrc
     rxPair = Rx
 
     def __init__(self, srcList, **kwargs):
diff --git a/SimPEG/EM/TDEM/__init__.py b/SimPEG/EM/TDEM/__init__.py
index 13010109..3c22d42d 100644
--- a/SimPEG/EM/TDEM/__init__.py
+++ b/SimPEG/EM/TDEM/__init__.py
@@ -1,3 +1,3 @@
 from TDEM import BaseTDEMProblem, Problem_b, Problem_e
 from FieldsTDEM import Fields, Fields_b
-from SurveyTDEM import Survey, BaseSrc, Rx
+from SurveyTDEM import Survey, Src, Rx
diff --git a/SimPEG/EM/TDEM_old/SurveyTDEM.py b/SimPEG/EM/TDEM_old/SurveyTDEM.py
index 338fd484..6b5aec2b 100644
--- a/SimPEG/EM/TDEM_old/SurveyTDEM.py
+++ b/SimPEG/EM/TDEM_old/SurveyTDEM.py
@@ -2,7 +2,7 @@ from SimPEG import Utils, Survey, np
 from SimPEG.Survey import BaseSurvey
 from SimPEG.EM.Utils import *
 from BaseTDEM import FieldsTDEM
-
+import SrcTDEM as Src
 
 class RxTDEM(Survey.BaseTimeRx):
 
@@ -87,7 +87,7 @@ class SrcTDEM_VMD_MVP(SrcTDEM):
     def getInitialFields(self, mesh):
         """Vertical magnetic dipole, magnetic vector potential"""
         if self.waveformType == "STEPOFF":
-            print ">> Step waveform: Non-zero initial condition"        
+            print ">> Step waveform: Non-zero initial condition"
             if mesh._meshType is 'CYL':
                 if mesh.isSymmetric:
                     MVP = MagneticDipoleVectorPotential(self.loc, mesh, 'Ey')
@@ -96,8 +96,8 @@ class SrcTDEM_VMD_MVP(SrcTDEM):
             elif mesh._meshType is 'TENSOR':
                 MVP = MagneticDipoleVectorPotential(self.loc, mesh, ['Ex','Ey','Ez'])
             else:
-                raise Exception('Unknown mesh for VMD') 
-            return {"b": mesh.edgeCurl*MVP}               
+                raise Exception('Unknown mesh for VMD')
+            return {"b": mesh.edgeCurl*MVP}
         elif self.waveformType == "GENERAL":
             print ">> General waveform: Zero initial condition"
             return {"b": np.zeros(mesh.nF)}
@@ -113,7 +113,7 @@ class SrcTDEM_VMD_MVP(SrcTDEM):
         elif mesh._meshType is 'TENSOR':
             MVP = MagneticDipoleVectorPotential(self.loc, mesh, ['Ex','Ey','Ez'])
         else:
-            raise Exception('Unknown mesh for VMD')            
+            raise Exception('Unknown mesh for VMD')
         return mesh.edgeCurl.T*MfMui*mesh.edgeCurl*MVP
 
 
@@ -122,7 +122,7 @@ class SrcTDEM_CircularLoop_MVP(SrcTDEM):
         self.loc = loc
         self.radius = radius
         self.waveformType = waveformType
-        SrcTDEM.__init__(self,rxList)        
+        SrcTDEM.__init__(self,rxList)
 
     def getInitialFields(self, mesh):
         """Circular Loop, magnetic vector potential"""
@@ -153,7 +153,7 @@ class SrcTDEM_CircularLoop_MVP(SrcTDEM):
         elif mesh._meshType is 'TENSOR':
             MVP = MagneticLoopVectorPotential(self.loc, mesh, ['Ex','Ey','Ez'], self.radius)
         else:
-            raise Exception('Unknown mesh for CircularLoop')            
+            raise Exception('Unknown mesh for CircularLoop')
         return mesh.edgeCurl.T*MfMui*mesh.edgeCurl*MVP
 
 
diff --git a/SimPEG/Examples/EM_FDEM_1D_Inversion.py b/SimPEG/Examples/EM_FDEM_1D_Inversion.py
index e76b2439..1556bf63 100644
--- a/SimPEG/Examples/EM_FDEM_1D_Inversion.py
+++ b/SimPEG/Examples/EM_FDEM_1D_Inversion.py
@@ -42,7 +42,7 @@ def run(plotIt=True):
         ax.grid(color='k', alpha=0.5, linestyle='dashed', linewidth=0.5)
 
 
-    rxOffset=10. 
+    rxOffset=10.
     bzi = EM.FDEM.Rx(np.array([[rxOffset, 0., 1e-3]]), 'bzi')
 
     freqs = np.logspace(1,3,10)
diff --git a/SimPEG/Examples/EM_TDEM_1D_Inversion.py b/SimPEG/Examples/EM_TDEM_1D_Inversion.py
index c92b972d..71ea0619 100644
--- a/SimPEG/Examples/EM_TDEM_1D_Inversion.py
+++ b/SimPEG/Examples/EM_TDEM_1D_Inversion.py
@@ -43,7 +43,7 @@ def run(plotIt=True):
 
     rxOffset=1e-3
     rx = EM.TDEM.Rx(np.array([[rxOffset, 0., 30]]), np.logspace(-5,-3, 31), 'bz')
-    src = EM.TDEM.SurveyTDEM.MagDipole([rx], loc=np.array([0., 0., 80]))
+    src = EM.TDEM.Src.MagDipole([rx], loc=np.array([0., 0., 80]))
     survey = EM.TDEM.Survey([src])
     prb = EM.TDEM.Problem_b(mesh, mapping=mapping)
 
diff --git a/tests/em/tdem/test_TDEM_b_DerivAdjoint.py b/tests/em/tdem/test_TDEM_b_DerivAdjoint.py
index c3ac40ba..085b4f1a 100644
--- a/tests/em/tdem/test_TDEM_b_DerivAdjoint.py
+++ b/tests/em/tdem/test_TDEM_b_DerivAdjoint.py
@@ -24,7 +24,7 @@ def setUp(prbtype='b', rxcomp='bz'):
 
     rxOffset = 10.
     rx = EM.TDEM.Rx(np.array([[rxOffset, 0., -1e-2]]), np.logspace(-4,-3, 20), rxcomp) #,]
-    src = EM.TDEM.SurveyTDEM.MagDipole([rx], loc=np.array([0., 0., 0.]))
+    src = EM.TDEM.Src.MagDipole([rx], loc=np.array([0., 0., 0.]))
 
     survey = EM.TDEM.Survey([src])