Question for those using Progressive Dynamics converters... November 30, 2008, 07:38:10 pm Yahoo Message Number: 97587Do you find the 'whistle' they emit to be objectionable, or do you hear it at all? I exchanged my first PD4645 because the noise was often loud, depending on load. The replacement is quieter, but still quite noticeable if it is otherwise quiet inside. Thanks for any input.Steve