More than 100 years ago, Jacques and Pierre Curie discovered that quartz crystals produced an electrical charge when deformed. They also found that the same crystals changed in dimension when subjected to an electric field. They called this phenomenon "piezo electricity"—derived from the Greek for ‘pressure electricity."

Piezoelectricity is electric polarization produced by mechanical strain  in certain crystals, the polarization being proportional to the amount of strain and changing polarity with it. The reverse is also true: an electrical polarization will induce a mechanical strain in piezoelectric crystals.

Ceramic or Piezo or Pressure Transducers (Pickups) capture an acoustic sound from the vibrating saddle piece rather than a magnetic capture of steel string vibrations. The result is the Acoustic/Electric sound.

Converting your Acoustic to Acoustic/Electric is not difficult. It basically involves loosening the strings and removing the saddle piece from the bridge and placing the pick up in the saddle piece bridge grove and then replacing the saddle piece and retuning.  For a permanent instal, consider drilling a small hole in the saddle to accommodate the signal wire. The links below will illustrate different methods of conversion.

We also have longer pickups for Classical Guitars which have a slightly wider bridge than a steel string Guitar.

Q. I can't tell from the pic but does this saddle insert REPLACE the current Saddle or reside BENEATH it?  And do you have any dimensions?  Last question, is this new or used item?

Thanks! Good Questions...the pickup resides under the saddle. The bone or plastic saddle sits on top of the transducer in the saddle slot of the bridge. The saddle puts pressure on the transducer and the string vibrations travel  through the saddle to reach the transducer. My Saddle is 2  13/16 in., the Transducer is 2  11/16 in. The transducer is New. We have a slightly larger transducer for use with Classical Guitars as the string spacing is a little wider.

You might want to take a peek at: http://www.sonica.org/guitar/cp80/custom/ These personalized (Your name in Gold on the Headstock) guitars are available for 499.00 in your choice of transparent basic colors and with or without the Mother of Pearl Inlay. Once in a while we have one on ebay. Delivery is 4-5 months. They are complete with pre-amp and equalizer. They are custom made of hand laid fiberglass and spurce top. Neck has truss rod of course.

You can see a page on the Pre-amp at:http://www.sonica.org/pickups/eq505/  and http://www.sonica.org/pickups/eq7545/
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