diff --git a/nifty5/domains/log_rg_space.py b/nifty5/domains/log_rg_space.py
index 3aabf68de347ffcbc574a5819ace5fd9a86ce068..740ac391b1500cca6c510ad42f6047a324fa1143 100644
--- a/nifty5/domains/log_rg_space.py
+++ b/nifty5/domains/log_rg_space.py
@@ -74,11 +74,9 @@ class LogRGSpace(StructuredDomain):
                 % (self.shape, self.harmonic))
 
     def get_default_codomain(self):
-        if self._harmonic:
-            raise ValueError("only supported for nonharmonic space")
         codomain_bindistances = 1. / (self.bindistances * self.shape)
         return LogRGSpace(self.shape, codomain_bindistances,
-                          np.zeros(len(self.shape)), True)
+                          self._t_0, True)
 
     def get_k_length_array(self):
         ib = dobj.ibegin_from_shape(self._shape)
diff --git a/nifty5/library/amplitude_model.py b/nifty5/library/amplitude_model.py
index 5f599503a22187c4cbed09efd8f3a07aced06427..1aa00ed24003d18561c13bca2e4949022b355b85 100644
--- a/nifty5/library/amplitude_model.py
+++ b/nifty5/library/amplitude_model.py
@@ -65,9 +65,9 @@ def make_amplitude_model(s_space, Npixdof, ceps_a, ceps_k, sm, sv, im, iv,
     p_space = PowerSpace(h_space)
     exp_transform = ExpTransform(p_space, Npixdof)
     logk_space = exp_transform.domain[0]
-    dof_space = logk_space.get_default_codomain()
+    qht = QHTOperator(target=logk_space)
+    dof_space = qht.domain[0]
     param_space = UnstructuredDomain(2)
-    qht = QHTOperator(dof_space, logk_space)
     sym = SymmetrizingOperator(logk_space)
 
     phi_mean = np.array([sm, im])
diff --git a/nifty5/operators/qht_operator.py b/nifty5/operators/qht_operator.py
index 3eebc338146c167b3ebc40b837291b00accccf0d..b5a30bbb8762b5a1071787eff61ae93510b33098 100644
--- a/nifty5/operators/qht_operator.py
+++ b/nifty5/operators/qht_operator.py
@@ -36,34 +36,28 @@ class QHTOperator(LinearOperator):
 
     Parameters
     ----------
-    domain : domain, tuple of domains or DomainTuple
-        The full input domain
+    target : domain, tuple of domains or DomainTuple
+        The full output domain
     space : int
         The index of the domain on which the operator acts.
-        domain[space] must be a harmonic LogRGSpace.
-    target : LogRGSpace
-        The target codomain of domain[space]
-        Must be a nonharmonic LogRGSpace.
+        target[space] must be a nonharmonic LogRGSpace.
     """
-    def __init__(self, domain, target, space=0):
-        self._domain = DomainTuple.make(domain)
-        self._space = infer_space(self._domain, space)
+    def __init__(self, target, space=0):
+        self._target = DomainTuple.make(target)
+        self._space = infer_space(self._target, space)
 
         from ..domains.log_rg_space import LogRGSpace
-        if not isinstance(self._domain[self._space], LogRGSpace):
-            raise ValueError("Domain[space] has to be a LogRGSpace!")
-        if not isinstance(target, LogRGSpace):
-            raise ValueError("Target has to be a LogRGSpace!")
+        if not isinstance(self._target[self._space], LogRGSpace):
+            raise ValueError("target[space] has to be a LogRGSpace!")
 
-        if not self._domain[self._space].harmonic:
+        if self._target[self._space].harmonic:
             raise TypeError(
-                "QHTOperator only works on a harmonic space")
-        if target.harmonic:
-            raise TypeError("Target is not a codomain of domain")
+                "target[space] must be a nonharmonic space")
 
-        self._target = [dom for dom in self._domain]
-        self._target[self._space] = target
-        self._target = DomainTuple.make(self._target)
+        self._domain = [dom for dom in self._target]
+        self._domain[self._space] = \
+            self._target[self._space].get_default_codomain()
+        self._domain = DomainTuple.make(self._domain)
 
     @property
     def domain(self):
diff --git a/test/test_operators/test_adjoint.py b/test/test_operators/test_adjoint.py
index f6f9e9542e5cd41d35eb7d9444164e663b2513cd..74cf970c27167a6b13095e603ff31784c9fc6903 100644
--- a/test/test_operators/test_adjoint.py
+++ b/test/test_operators/test_adjoint.py
@@ -143,8 +143,6 @@ class Consistency_Tests(unittest.TestCase):
                        ift.LogRGSpace(17, [3.], [.7])), 1)],
                     [np.float64]))
     def testQHTOperator(self, args, dtype):
-        dom = ift.DomainTuple.make(args[0])
-        tgt = list(dom)
-        tgt[args[1]] = tgt[args[1]].get_default_codomain()
-        op = ift.QHTOperator(tgt, dom[args[1]], args[1])
+        tgt = ift.DomainTuple.make(args[0])
+        op = ift.QHTOperator(tgt, args[1])
         ift.extra.consistency_check(op, dtype, dtype)