Cap question

[GeToChKn]

Does it really matter if a schematic calls for a film cap and we use a electrolytic capacitor instead?  My local electronic store has all kinds of electrolytic capacitor but very little film capacitors available.  Should I do the back to back trick with the negative connected of two similar electrolytic capacitor to make a regular cap?

[Shepherd]

Some people avoid electrolytic capacitors as much as possible.

At any rate, doubling up takes a lot of space away from you very quickly.

[petemoore]

  The electro has no idea what it'll be like when placed somewhere in something, differences may actually occur when they're noticed.
  Also true of ceramic type caps.
  Small film caps may be used and even augment electrolytic ''high speed'' processing [high frequency] sometimes.
  I'd say get film types poly or whatever material suits your needs, and then when the values get 'so' big and space isn't that big, use elecrolytics.

[anchovie]

Does it really matter if a schematic calls for a film cap and we use a electrolytic capacitor instead?  My local electronic store has all kinds of electrolytic capacitor but very little film capacitors available.  Should I do the back to back trick with the negative connected of two similar electrolytic capacitor to make a regular cap?

What kinds of values are we talking about here? If a schematic wants a 10nF film cap it's unlikely you'll get a 10nF electrolytic.

[isildur100]

Some people in hi-fi believe that different types of capacitors do not all sound the same. Some sound better than others. Read this here:

http://greygum.net/sbench/sbench102/caps.html

However, in the stomp box world, it seems it does not really matter, as long as you use capacitors with the appropriate value and voltage rating. An analog effect pedal is probably not hi-fi enough to be able to hear a noticeable difference whether you use electrolytic or film or if you use super high quality hi-fi caps or cheaper general purpose ones etc.

[Skruffyhound]

But remember, as R.G. is always telling us, you have to be sure that there will never at any time be any flow of current in the wrong direction for a polarized electrolytic. If you can guarantee that, then you can use them.
Bear in mind though that they are a weak link because of the above mentioned problem, and they don't just die necessarily, they can struggle on with increasing damage for some time, which makes trouble shooting more tricky.
Metal film caps are rugged, and if you are having trouble finding them in the shop, collect some junk video/audio/tv appliances get yourself a magnifying glass and start ripping stuff apart, don't worry how old the junk is, in fact the older the better