[quote name='munkonthehill' post='947917' date='Sep 7 2010, 08:15 AM']I just think it may save my time in telling me if an ext. cab would be required for maximum output of an amp,,,,,,simple[/quote]
I think the safest option would be to treat a combo as if it was an amp capable of running at 4 ohms & comes with an 8 ohm cab as there are only a handful that put out full power without an ext cab.