Sometimes we ask young children odd-sounding questions that are word game riddles designed to challenge their typical way of thinking.  Every child has probably been asked “What has hands but doesn’t clap?” Eventually, they all know to answer “a clock!” 


But sometimes, these odd-sounding questions actually have unique and weird answers.  Take, for example, the question of “What do guitars and nuclear power plants have in common?”  Read on to find out the answer. 


You may be surprised to know both nuclear power plants and guitars share components.  One of the most interesting shared components between these two very different things is a certain type of capacitor, called a paper and oil capacitor, which was often used in early circuit boards that were part of nuclear turbine management systems like the GE Mark II.   Paper and oil capacitors, otherwise known as film-based power capacitors, were metallized paper or foil-wrapped capacitors with an electrical insulator made from paper impregnated with oil.  They were also sometimes impregnated with wax or epoxy. 


These same paper and oil capacitors are now often prized by guitarists for their bright tone. The capacitor is connected to the tone knob located on the guitar’s front surface.  As the tone knob is turned down from its highest position toward its bottom end, the capacitor filters certain frequencies of sound flowing through from the guitar’s pickup to its amplifier, creating a more muffled timbre.   The folks over at New Perspectives Music have a great demonstration on how that works if you’re interested.


So why do these capacitors work differently in handling tone than other capacitors?  Some people say they don’t--that it’s all just hype. Others insist these paper in oil capacitors produce a certain ‘vintage’ tone that cannot be duplicated.  Also, they avoid issues that happen with other types of capacitors, such as the tendency for ceramic caps to pick up sound like a small microphone. Atlantic Quality Design did a great test on tone capacitors, with results that can be found here.