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previous: Steve A. Bic: &nb... -- 6/14/1999 9:50 PM

Re: Tantalum VS. FILM!

6/15/1999 4:11 AM
BicBogartPeas	Re: Tantalum VS. FILM! Steve, Technically speaking, I would call the 225P which you described a foil cap since the capacitor plates are made of thin foil. This may sound confusing since the cap is of the polyester film variety. A more precise way of describing what I referred to as a film cap would be the term 'metalized film capacitor' in which the film itself is made conductive by spraying an extremely thin coating of aluminum on it. If you ever see metalized film up close you will know what I mean. You can hold it up to the light and actually see through the metal. The metallic coating is that thin. In general, foil caps sound better than metallized film. However, there is a significant number of people who prefer metalized film over foil for the following reasons: 1) metalized film caps are a lot smaller physically than foil caps, 2) metalized film caps have lower temperature coefficients than foil caps since the metal plates of foil caps expand slightly when heated, and 3) metalized film caps tend to be self healing since a short across the dielectric quickly vaporizes the metalized area involved in the short, thereby causing the short to disappear. My preference as far as Sprague goes is the 715P Orange Drop which is a polypropylene/foil that sounds well balanced and is slightly brighter than the 225P but not objectionably so. A good inexpensive substitute for the 715P is the Xicon MPP series of metalized film caps available from Mouser (some metalized film caps actually do sound good!). If money is not an objection, then the ultimate capacitor, in my humble opinion, for enhancing high frequencies is the Musical Interface Technologies (MIT) Polystyrene MultiCap which is a non-inductive foil coaxial cap. Hovland MusicCaps and Kimber-Kaps also get high ratings and would be an appropriate substitute for an MIT. Thanks for your additional insites on caps. I always find the topic intersting. BicBogartPeas

6/15/1999 4:11 AM

BicBogartPeas

Re: Tantalum VS. FILM!

Steve,

Technically speaking, I would call the 225P which you described a foil cap since the capacitor plates are made of thin foil. This may sound confusing since the cap is of the polyester film variety. A more precise way of describing what I referred to as a film cap would be the term 'metalized film capacitor' in which the film itself is made conductive by spraying an extremely thin coating of aluminum on it. If you ever see metalized film up close you will know what I mean. You can hold it up to the light and actually see through the metal. The metallic coating is that thin.

In general, foil caps sound better than metallized film. However, there is a significant number of people who prefer metalized film over foil for the following reasons: 1) metalized film caps are a lot smaller physically than foil caps, 2) metalized film caps have lower temperature coefficients than foil caps since the metal plates of foil caps expand slightly when heated, and 3) metalized film caps tend to be self healing since a short across the dielectric quickly vaporizes the metalized area involved in the short, thereby causing the short to disappear.

My preference as far as Sprague goes is the 715P Orange Drop which is a polypropylene/foil that sounds well balanced and is slightly brighter than the 225P but not objectionably so. A good inexpensive substitute for the 715P is the Xicon MPP series of metalized film caps available from Mouser (some metalized film caps actually do sound good!). If money is not an objection, then the ultimate capacitor, in my humble opinion, for enhancing high frequencies is the Musical Interface Technologies (MIT) Polystyrene MultiCap which is a non-inductive foil coaxial cap. Hovland MusicCaps and Kimber-Kaps also get high ratings and would be an appropriate substitute for an MIT.

Thanks for your additional insites on caps. I always find the topic intersting.

BicBogartPeas