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Metallized Film Capacitors

11/20/2002 2:12 AM
Metallized Film Capacitors
I was cruising Robert Keeley's page and he talks about modding a Boss DS-1. He mentions replacing the "electrolytic" caps with "metallized film" caps.  
My question is since the electrolytics are polarized, how is this possible? Am I correct in assuming that the film caps are nonpolarized?  
Thanks in advance,  
11/20/2002 5:05 AM

You can replace an electro of small value with a non polarized capacitor. The polarization of an electro is not an advantage, it's a disadvantage. You have to orient the Plus side to the side of the circuit that has the more positive voltage.  
The reason why electros are used most often is for there large values for cheap cost and small size. For instance, in a Fender blender or Foxx tone machine, all the coupling caps are 10uf. If you could ever find a poly cap in that large a value, it would be expensive and....*HUGE*.  
I like the tone of poly caps, and the metalized caps by AVX are available up to 1uf and I like to replace the 1uf couple caps in muffs and TS pedals with the them. The downside is that poly caps this big will cost you. To buy 1 AVX 1uF metalpoly from Mouser electronics would cost you $1.30. If youwanted to buy 100 of them (which I did) the cost is $87.00, or $.87 each.
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12/19/2002 6:09 PM
IMHO electrolytics have no place in audio circuits other than for filtering in power supply circuits. To my ears, electrolytics have a "grainy" sound when used as coupling caps. Get rid of them.  
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