diff --git a/boxtree/tools.py b/boxtree/tools.py
index 9c74d960aac4e3c696a9d2e8ade6d3ed8aa13e3f..b1d223e40a22bec0c44d4387502eb5ff5c35d57d 100644
--- a/boxtree/tools.py
+++ b/boxtree/tools.py
@@ -276,8 +276,8 @@ class DeviceDataRecord(Record):
         def transform_val(val):
             from pyopencl.algorithm import BuiltList
             if isinstance(val, np.ndarray) and val.dtype == object:
-                from pytools.obj_array import with_object_array_or_scalar
-                return with_object_array_or_scalar(f, val)
+                from pytools.obj_array import obj_array_vectorize
+                return obj_array_vectorize(f, val)
             elif isinstance(val, list):
                 return [transform_val(i) for i in val]
             elif isinstance(val, BuiltList):
diff --git a/boxtree/tree_build.py b/boxtree/tree_build.py
index 38c69b7e38e0011d5652a01c9c7856678b2df70b..cf4e80b077e53e0eb4a3797b274556a255bc3334 100644
--- a/boxtree/tree_build.py
+++ b/boxtree/tree_build.py
@@ -247,10 +247,10 @@ class TreeBuilder(object):
             # Targets weren't specified. Sources are also targets. Let's
             # call them "srcntgts".
 
-            from pytools.obj_array import is_obj_array, make_obj_array
-            if is_obj_array(particles):
+            if isinstance(particles, np.ndarray) and particles.dtype.char == "O":
                 srcntgts = particles
             else:
+                from pytools.obj_array import make_obj_array
                 srcntgts = make_obj_array([
                     p.with_queue(queue).copy() for p in particles
                     ])