diff --git a/examples/cuda/vector_add_observers_pmt.py b/examples/cuda/vector_add_observers_pmt.py
index bd8b2d4e..1f6e491d 100755
--- a/examples/cuda/vector_add_observers_pmt.py
+++ b/examples/cuda/vector_add_observers_pmt.py
@@ -31,7 +31,7 @@ def tune():
     tune_params = dict()
     tune_params["block_size_x"] = [128+64*i for i in range(15)]
 
-    pmtobserver = PMTObserver(["nvidia", "rapl"])
+    pmtobserver = PMTObserver([("nvidia", 0), "rapl"])
 
     metrics = OrderedDict()
     metrics["GPU W"] = lambda p: p["nvidia_power"]
diff --git a/kernel_tuner/observers/pmt.py b/kernel_tuner/observers/pmt.py
index 21d777fb..bb1d76bd 100644
--- a/kernel_tuner/observers/pmt.py
+++ b/kernel_tuner/observers/pmt.py
@@ -38,8 +38,8 @@ def __init__(self, observable=None):
         if type(observable) is dict:
             pass
         elif type(observable) is list:
-            # user specifies a list of platforms as observable
-            observable = dict([(obs, 0) for obs in observable])
+            # user specifies a list of platforms as observable, optionally with an argument
+            observable = dict([obs if isinstance(obs, tuple) else (obs, None) for obs in observable])
         else:
             # User specifices a string (single platform) as observable
             observable = {observable: None}