polarized vs. non polarized caps

[mordechai]

This may be a pretty dumb question, but what happens if I use a non-polarized capacitor instead of a polarized capacitor in some spots?  I just saw a fuzz face type circuit where all the caps appear to be non polarized...and I am wondering what effect this may have.

[ckyvick]

There are arguments that non polarized film caps sound better than polarized electrolytics in the audio path. You could also use polarized tantalum caps because np film caps start to cost too much once you get over 1uf in most cases.
When they are not in the direct audio path people usually don't care either way. I have not played with enough fuzz circuits to verify this but it is what people say. Heres a site to look over:
http://www.beavisaudio.com/techpages/Caps/

[R.G.]

This may be a pretty dumb question, but what happens if I use a non-polarized capacitor instead of a polarized capacitor in some spots?  I just saw a fuzz face type circuit where all the caps appear to be non polarized...and I am wondering what effect this may have.

You can use a non polarized cap of the same capacitance value wherever there is a polarized one. To a first order, it makes no difference. As to the fine tonal differences, you're going to have to mess with that and listen for yourself. I'd be willing to bet a moderate sum that you could not tell the difference in a blind listening test though.

[mordechai]

Thanks for the tips.  RG, a question -- if I can use non-polarized cap in place of a polarized one, can I use a polarized cap in place of a non-polarized one?

[R.G.]

if I can use non-polarized cap in place of a polarized one, can I use a polarized cap in place of a non-polarized one?

In general, no, not unless the non polarized one was already being used in a polarized setup, which does sometimes happen.

The bottom line is that a polarized cap may never get reversed by the instantaneous voltage across it. As long as that's true, you can use polarized. Otherwise, if the voltage across the cap is reversed even instantaneously, you should use NP.

[ashcat_lt]

Isn't there a way to use 2 polarized caps in opposing directions in place of an NP one?  Could have sworn I read something about that somewhere...

[R.G.]

Isn't there a way to use 2 polarized caps in opposing directions in place of an NP one?  Could have sworn I read something about that somewhere...

Yes there is. You connect them positive to positive or negative to negative, and if you're doing it right, you connect two schottky diodes reverse biased, on on each cap. The schottky diodes support a lower voltage than the cap forward conduction voltage.

But it's only what you do when you can't do anything else.

[Cliff Schecht]

There are benefits for using non-polarized caps in certain places. A good example is decoupling where the low ESR of ceramic caps will almost always benefit power supply decoupling. They also make special purpose bipolar electrolytic capacitors for audio. Nichicon makes quite a few flavors with different characteristics. These improvements may not be so audible for relatively lo-fi guitar pedals but they do make a heck of a difference in hifi and studio gear.

[RedHouse]

You can use a non polarized cap of the same capacitance value wherever there is a polarized one. To a first order, it makes no difference. As to the fine tonal differences, you're going to have to mess with that and listen for yourself. I'd be willing to bet a moderate sum that you could not tell the difference in a blind listening test though.

(in my best Paul McCartney voice)....

"Whisper words of wisdon, ...let it be, let it be.".

[amptramp]

I have a Univox U-65G amplifier where the tremolo circuit is built with three 1 uF polarized caps.  The problem is, a phase-shift oscillator will reverse the polarity of the cap voltage.  So I replaced them all with non-polar 1 uF caps and the tremolo that had not been working started working.  Don't count on the design being right in the first place.