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From: kludge@grissom.larc.nasa.gov ( Scott Dorsey)
Newsgroups: sci.electronics
Subject: Re: How do I choose a capacitor type ?
Keywords: distortion capacitors
Message-ID: <1991Feb5.211414.16831@news.larc.nasa.gov>
Date: 5 Feb 91 21:14:14 GMT
References: <64@owl.ukc.ac.uk> <1991Feb5.185727.14775@news.larc.nasa.gov> <4193@eastapps.East.Sun.COM>
Sender: news@news.larc.nasa.gov (USENET Network News)
Reply-To: kludge@grissom.larc.nasa.gov ( Scott Dorsey)
Organization: NASA Langley Research Center
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In article <4193@eastapps.East.Sun.COM> gsteckel@east.sun.com (Geoff Steckel - Sun BOS Hardware CONTRACTOR) writes:
I wrote:
>> For coupling capacitors in audio circuits (DC blocking caps), use polyester
>> or polypropylene caps.
>
>The `true believers' in audio wonderfulness would never use a polyester cap
>anywhere.  In fact, they do have a large `dissipation factor' and apparently
>are somewhat nonlinear, as are `high-K' ceramics (with Z5U or Y5V tempco
>markings).
>I would recommend polystyrene or polypropylene film caps for wonderful coupling
>caps, or low-K (NPO) ceramic or mica caps for small values ( < 100 pF).
>They will be much larger physically and cost much more than the polyester caps.

That's right.  Make sure you buy only Wondercaps or some expensive foreign
brand.  Only polypropylene will do, and the harder they are to get, the better
they are.

Anyway, polyesters are usually quite fine capacitors for coupling, although
at high voltages (in in working with tube gear), the polypropylenes have a
good upper hand.  Ceramics are bad news.  Electrolytics
in the audio path are bad news.

Please return the rest of this discussion to rec.audio.high-end
--scott